diff --git a/nexus/db-queries/src/db/datastore/affinity.rs b/nexus/db-queries/src/db/datastore/affinity.rs
index 7cad11c1e24..b97ace07a0d 100644
--- a/nexus/db-queries/src/db/datastore/affinity.rs
+++ b/nexus/db-queries/src/db/datastore/affinity.rs
@@ -29,6 +29,7 @@ use crate::db::model::Project;
 use crate::db::model::VmmState;
 use crate::db::model::VmmStateEnum;
 use crate::db::pagination::RawPaginator;
+use crate::db::pagination::paginated;
 use crate::transaction_retry::OptionalError;
 use async_bb8_diesel::AsyncRunQueryDsl;
 use chrono::Utc;
@@ -48,9 +49,88 @@ use omicron_uuid_kinds::AffinityGroupUuid;
 use omicron_uuid_kinds::AntiAffinityGroupUuid;
 use omicron_uuid_kinds::GenericUuid;
 use omicron_uuid_kinds::InstanceUuid;
+use ref_cast::RefCast;
 use uuid::Uuid;
 
 impl DataStore {
+    /// List affinity groups associated with a given instance
+    pub async fn instance_list_affinity_groups(
+        &self,
+        opctx: &OpContext,
+        authz_instance: &authz::Instance,
+        pagparams: &PaginatedBy<'_>,
+    ) -> ListResultVec<AffinityGroup> {
+        use db::schema::affinity_group::dsl as group_dsl;
+        use db::schema::affinity_group_instance_membership::dsl as membership_dsl;
+
+        opctx.authorize(authz::Action::ListChildren, authz_instance).await?;
+
+        match pagparams {
+            PaginatedBy::Id(pagparams) => {
+                paginated(group_dsl::affinity_group, group_dsl::id, &pagparams)
+            }
+            PaginatedBy::Name(pagparams) => paginated(
+                group_dsl::affinity_group,
+                group_dsl::name,
+                &pagparams.map_name(|n| Name::ref_cast(n)),
+            ),
+        }
+        .filter(group_dsl::time_deleted.is_null())
+        .inner_join(
+            membership_dsl::affinity_group_instance_membership.on(
+                membership_dsl::instance_id
+                    .eq(authz_instance.id())
+                    .and(membership_dsl::group_id.eq(group_dsl::id)),
+            ),
+        )
+        .select(AffinityGroup::as_select())
+        .load_async::<AffinityGroup>(
+            &*self.pool_connection_authorized(opctx).await?,
+        )
+        .await
+        .map_err(|e| public_error_from_diesel(e, ErrorHandler::Server))
+    }
+
+    /// List anti-affinity groups associated with a given instance
+    pub async fn instance_list_anti_affinity_groups(
+        &self,
+        opctx: &OpContext,
+        authz_instance: &authz::Instance,
+        pagparams: &PaginatedBy<'_>,
+    ) -> ListResultVec<AntiAffinityGroup> {
+        use db::schema::anti_affinity_group::dsl as group_dsl;
+        use db::schema::anti_affinity_group_instance_membership::dsl as membership_dsl;
+
+        opctx.authorize(authz::Action::ListChildren, authz_instance).await?;
+
+        match pagparams {
+            PaginatedBy::Id(pagparams) => paginated(
+                group_dsl::anti_affinity_group,
+                group_dsl::id,
+                &pagparams,
+            ),
+            PaginatedBy::Name(pagparams) => paginated(
+                group_dsl::anti_affinity_group,
+                group_dsl::name,
+                &pagparams.map_name(|n| Name::ref_cast(n)),
+            ),
+        }
+        .filter(group_dsl::time_deleted.is_null())
+        .inner_join(
+            membership_dsl::anti_affinity_group_instance_membership.on(
+                membership_dsl::instance_id
+                    .eq(authz_instance.id())
+                    .and(membership_dsl::group_id.eq(group_dsl::id)),
+            ),
+        )
+        .select(AntiAffinityGroup::as_select())
+        .load_async::<AntiAffinityGroup>(
+            &*self.pool_connection_authorized(opctx).await?,
+        )
+        .await
+        .map_err(|e| public_error_from_diesel(e, ErrorHandler::Server))
+    }
+
     pub async fn affinity_group_list(
         &self,
         opctx: &OpContext,
diff --git a/nexus/external-api/output/nexus_tags.txt b/nexus/external-api/output/nexus_tags.txt
index a94d31314d3..6e1e119b5de 100644
--- a/nexus/external-api/output/nexus_tags.txt
+++ b/nexus/external-api/output/nexus_tags.txt
@@ -75,6 +75,8 @@ image_view                               GET      /v1/images/{image}
 
 API operations found with tag "instances"
 OPERATION ID                             METHOD   URL PATH
+instance_affinity_group_list             GET      /v1/instances/{instance}/affinity-groups
+instance_anti_affinity_group_list        GET      /v1/instances/{instance}/anti-affinity-groups
 instance_create                          POST     /v1/instances
 instance_delete                          DELETE   /v1/instances/{instance}
 instance_disk_attach                     POST     /v1/instances/{instance}/disks/attach
diff --git a/nexus/external-api/src/lib.rs b/nexus/external-api/src/lib.rs
index e29dedf04a0..a5e8654e30e 100644
--- a/nexus/external-api/src/lib.rs
+++ b/nexus/external-api/src/lib.rs
@@ -1264,6 +1264,34 @@ pub trait NexusExternalApi {
         disk_to_detach: TypedBody<params::DiskPath>,
     ) -> Result<HttpResponseAccepted<Disk>, HttpError>;
 
+    /// List affinity groups containing instance
+    #[endpoint {
+        method = GET,
+        path = "/v1/instances/{instance}/affinity-groups",
+        tags = ["instances"],
+    }]
+    async fn instance_affinity_group_list(
+        rqctx: RequestContext<Self::Context>,
+        query_params: Query<
+            PaginatedByNameOrId<params::OptionalProjectSelector>,
+        >,
+        path_params: Path<params::InstancePath>,
+    ) -> Result<HttpResponseOk<ResultsPage<views::AffinityGroup>>, HttpError>;
+
+    /// List anti-affinity groups containing instance
+    #[endpoint {
+        method = GET,
+        path = "/v1/instances/{instance}/anti-affinity-groups",
+        tags = ["instances"],
+    }]
+    async fn instance_anti_affinity_group_list(
+        rqctx: RequestContext<Self::Context>,
+        query_params: Query<
+            PaginatedByNameOrId<params::OptionalProjectSelector>,
+        >,
+        path_params: Path<params::InstancePath>,
+    ) -> Result<HttpResponseOk<ResultsPage<views::AntiAffinityGroup>>, HttpError>;
+
     // Affinity Groups
 
     /// List affinity groups
diff --git a/nexus/src/app/instance.rs b/nexus/src/app/instance.rs
index b0577aaf6e2..cf04c28f870 100644
--- a/nexus/src/app/instance.rs
+++ b/nexus/src/app/instance.rs
@@ -1523,6 +1523,38 @@ impl super::Nexus {
         Ok(disk)
     }
 
+    /// Lists affinity groups to which this instance belongs
+    pub(crate) async fn instance_list_affinity_groups(
+        &self,
+        opctx: &OpContext,
+        instance_lookup: &lookup::Instance<'_>,
+        pagparams: &PaginatedBy<'_>,
+    ) -> ListResultVec<db::model::AffinityGroup> {
+        let (.., authz_instance) =
+            instance_lookup.lookup_for(authz::Action::ListChildren).await?;
+        self.db_datastore
+            .instance_list_affinity_groups(opctx, &authz_instance, pagparams)
+            .await
+    }
+
+    /// Lists anti-affinity groups to which this instance belongs
+    pub(crate) async fn instance_list_anti_affinity_groups(
+        &self,
+        opctx: &OpContext,
+        instance_lookup: &lookup::Instance<'_>,
+        pagparams: &PaginatedBy<'_>,
+    ) -> ListResultVec<db::model::AntiAffinityGroup> {
+        let (.., authz_instance) =
+            instance_lookup.lookup_for(authz::Action::ListChildren).await?;
+        self.db_datastore
+            .instance_list_anti_affinity_groups(
+                opctx,
+                &authz_instance,
+                pagparams,
+            )
+            .await
+    }
+
     /// Invoked by a sled agent to publish an updated runtime state for an
     /// Instance.
     pub(crate) async fn notify_vmm_updated(
diff --git a/nexus/src/external_api/http_entrypoints.rs b/nexus/src/external_api/http_entrypoints.rs
index 1508ff51ec2..2eb053f46e5 100644
--- a/nexus/src/external_api/http_entrypoints.rs
+++ b/nexus/src/external_api/http_entrypoints.rs
@@ -2508,6 +2508,100 @@ impl NexusExternalApi for NexusExternalApiImpl {
             .await
     }
 
+    async fn instance_affinity_group_list(
+        rqctx: RequestContext<ApiContext>,
+        query_params: Query<
+            PaginatedByNameOrId<params::OptionalProjectSelector>,
+        >,
+        path_params: Path<params::InstancePath>,
+    ) -> Result<HttpResponseOk<ResultsPage<views::AffinityGroup>>, HttpError>
+    {
+        let apictx = rqctx.context();
+        let handler = async {
+            let nexus = &apictx.context.nexus;
+            let path = path_params.into_inner();
+            let query = query_params.into_inner();
+            let pag_params = data_page_params_for(&rqctx, &query)?;
+            let scan_params = ScanByNameOrId::from_query(&query)?;
+            let paginated_by = name_or_id_pagination(&pag_params, scan_params)?;
+            let opctx =
+                crate::context::op_context_for_external_api(&rqctx).await?;
+            let instance_selector = params::InstanceSelector {
+                project: scan_params.selector.project.clone(),
+                instance: path.instance,
+            };
+            let instance_lookup =
+                nexus.instance_lookup(&opctx, instance_selector)?;
+            let groups = nexus
+                .instance_list_affinity_groups(
+                    &opctx,
+                    &instance_lookup,
+                    &paginated_by,
+                )
+                .await?
+                .into_iter()
+                .map(|g| g.into())
+                .collect();
+            Ok(HttpResponseOk(ScanByNameOrId::results_page(
+                &query,
+                groups,
+                &marker_for_name_or_id,
+            )?))
+        };
+        apictx
+            .context
+            .external_latencies
+            .instrument_dropshot_handler(&rqctx, handler)
+            .await
+    }
+
+    async fn instance_anti_affinity_group_list(
+        rqctx: RequestContext<ApiContext>,
+        query_params: Query<
+            PaginatedByNameOrId<params::OptionalProjectSelector>,
+        >,
+        path_params: Path<params::InstancePath>,
+    ) -> Result<HttpResponseOk<ResultsPage<views::AntiAffinityGroup>>, HttpError>
+    {
+        let apictx = rqctx.context();
+        let handler = async {
+            let nexus = &apictx.context.nexus;
+            let path = path_params.into_inner();
+            let query = query_params.into_inner();
+            let pag_params = data_page_params_for(&rqctx, &query)?;
+            let scan_params = ScanByNameOrId::from_query(&query)?;
+            let paginated_by = name_or_id_pagination(&pag_params, scan_params)?;
+            let opctx =
+                crate::context::op_context_for_external_api(&rqctx).await?;
+            let instance_selector = params::InstanceSelector {
+                project: scan_params.selector.project.clone(),
+                instance: path.instance,
+            };
+            let instance_lookup =
+                nexus.instance_lookup(&opctx, instance_selector)?;
+            let groups = nexus
+                .instance_list_anti_affinity_groups(
+                    &opctx,
+                    &instance_lookup,
+                    &paginated_by,
+                )
+                .await?
+                .into_iter()
+                .map(|g| g.into())
+                .collect();
+            Ok(HttpResponseOk(ScanByNameOrId::results_page(
+                &query,
+                groups,
+                &marker_for_name_or_id,
+            )?))
+        };
+        apictx
+            .context
+            .external_latencies
+            .instrument_dropshot_handler(&rqctx, handler)
+            .await
+    }
+
     // Affinity Groups
 
     async fn affinity_group_list(
diff --git a/nexus/tests/integration_tests/affinity.rs b/nexus/tests/integration_tests/affinity.rs
index debac93c0e1..a2299606a64 100644
--- a/nexus/tests/integration_tests/affinity.rs
+++ b/nexus/tests/integration_tests/affinity.rs
@@ -75,6 +75,11 @@ impl<T: AffinityGroupish> ProjectScopedApiHelper<'_, T> {
         .await
     }
 
+    async fn instance_groups_list(&self, instance: &str) -> Vec<T::Group> {
+        let url = instance_groups_url(T::URL_COMPONENT, instance, self.project);
+        objects_list_page_authz(&self.client, &url).await.items
+    }
+
     async fn groups_list(&self) -> Vec<T::Group> {
         let url = groups_url(T::URL_COMPONENT, self.project);
         objects_list_page_authz(&self.client, &url).await.items
@@ -401,6 +406,15 @@ impl AffinityGroupish for AntiAffinityType {
     }
 }
 
+fn instance_groups_url(
+    ty: &str,
+    instance: &str,
+    project: Option<&str>,
+) -> String {
+    let query_params = project_query_param_suffix(project);
+    format!("/v1/instances/{instance}/{ty}{query_params}")
+}
+
 fn groups_url(ty: &str, project: Option<&str>) -> String {
     let query_params = project_query_param_suffix(project);
     format!("/v1/{ty}{query_params}")
@@ -755,6 +769,49 @@ async fn test_group_crud<T: AffinityGroupish>(client: &ClientTestContext) {
     assert!(groups.is_empty());
 }
 
+#[nexus_test]
+async fn test_affinity_instance_group_list(
+    cptestctx: &ControlPlaneTestContext,
+) {
+    let external_client = &cptestctx.external_client;
+    test_instance_group_list::<AffinityType>(external_client).await;
+}
+
+#[nexus_test]
+async fn test_anti_affinity_instance_group_list(
+    cptestctx: &ControlPlaneTestContext,
+) {
+    let external_client = &cptestctx.external_client;
+    test_instance_group_list::<AntiAffinityType>(external_client).await;
+}
+
+async fn test_instance_group_list<T: AffinityGroupish>(
+    client: &ClientTestContext,
+) {
+    const PROJECT_NAME: &'static str = "test-project";
+
+    let api = ApiHelper::new(client);
+
+    // Create an IP pool and project that we'll use for testing.
+    create_default_ip_pool(&client).await;
+    api.create_project(PROJECT_NAME).await;
+
+    let project_api = api.use_project::<T>(PROJECT_NAME);
+
+    project_api.create_stopped_instance("test-instance").await;
+    let groups = project_api.instance_groups_list("test-instance").await;
+    assert!(groups.is_empty(), "New instance should not belong to any groups");
+
+    project_api.group_create("yes-group").await;
+    project_api.group_create("no-group").await;
+
+    project_api.group_member_add("yes-group", "test-instance").await;
+
+    let groups = project_api.instance_groups_list("test-instance").await;
+    assert_eq!(groups.len(), 1);
+    assert_eq!(groups[0].identity().name, "yes-group");
+}
+
 #[nexus_test]
 async fn test_affinity_group_project_selector(
     cptestctx: &ControlPlaneTestContext,
diff --git a/nexus/tests/integration_tests/endpoints.rs b/nexus/tests/integration_tests/endpoints.rs
index a606a0c94c2..1cb28dac8dc 100644
--- a/nexus/tests/integration_tests/endpoints.rs
+++ b/nexus/tests/integration_tests/endpoints.rs
@@ -596,6 +596,20 @@ pub static DEMO_INSTANCE_DISKS_DETACH_URL: LazyLock<String> =
             *DEMO_INSTANCE_NAME, *DEMO_PROJECT_SELECTOR
         )
     });
+pub static DEMO_INSTANCE_AFFINITY_GROUPS_URL: LazyLock<String> =
+    LazyLock::new(|| {
+        format!(
+            "/v1/instances/{}/affinity-groups?{}",
+            *DEMO_INSTANCE_NAME, *DEMO_PROJECT_SELECTOR
+        )
+    });
+pub static DEMO_INSTANCE_ANTI_AFFINITY_GROUPS_URL: LazyLock<String> =
+    LazyLock::new(|| {
+        format!(
+            "/v1/instances/{}/anti-affinity-groups?{}",
+            *DEMO_INSTANCE_NAME, *DEMO_PROJECT_SELECTOR
+        )
+    });
 pub static DEMO_INSTANCE_EPHEMERAL_IP_URL: LazyLock<String> =
     LazyLock::new(|| {
         format!(
@@ -1910,6 +1924,18 @@ pub static VERIFY_ENDPOINTS: LazyLock<Vec<VerifyEndpoint>> =
                     .unwrap(),
                 )],
             },
+            VerifyEndpoint {
+                url: &DEMO_INSTANCE_AFFINITY_GROUPS_URL,
+                visibility: Visibility::Protected,
+                unprivileged_access: UnprivilegedAccess::None,
+                allowed_methods: vec![AllowedMethod::Get],
+            },
+            VerifyEndpoint {
+                url: &DEMO_INSTANCE_ANTI_AFFINITY_GROUPS_URL,
+                visibility: Visibility::Protected,
+                unprivileged_access: UnprivilegedAccess::None,
+                allowed_methods: vec![AllowedMethod::Get],
+            },
             /* Affinity Groups */
             VerifyEndpoint {
                 url: &DEMO_PROJECT_URL_AFFINITY_GROUPS,
diff --git a/openapi/nexus.json b/openapi/nexus.json
index f442c455f19..25ae52300da 100644
--- a/openapi/nexus.json
+++ b/openapi/nexus.json
@@ -3280,6 +3280,158 @@
         }
       }
     },
+    "/v1/instances/{instance}/affinity-groups": {
+      "get": {
+        "tags": [
+          "instances"
+        ],
+        "summary": "List affinity groups containing instance",
+        "operationId": "instance_affinity_group_list",
+        "parameters": [
+          {
+            "in": "query",
+            "name": "limit",
+            "description": "Maximum number of items returned by a single call",
+            "schema": {
+              "nullable": true,
+              "type": "integer",
+              "format": "uint32",
+              "minimum": 1
+            }
+          },
+          {
+            "in": "query",
+            "name": "page_token",
+            "description": "Token returned by previous call to retrieve the subsequent page",
+            "schema": {
+              "nullable": true,
+              "type": "string"
+            }
+          },
+          {
+            "in": "query",
+            "name": "project",
+            "description": "Name or ID of the project",
+            "schema": {
+              "$ref": "#/components/schemas/NameOrId"
+            }
+          },
+          {
+            "in": "query",
+            "name": "sort_by",
+            "schema": {
+              "$ref": "#/components/schemas/NameOrIdSortMode"
+            }
+          },
+          {
+            "in": "path",
+            "name": "instance",
+            "description": "Name or ID of the instance",
+            "required": true,
+            "schema": {
+              "$ref": "#/components/schemas/NameOrId"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "successful operation",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/AffinityGroupResultsPage"
+                }
+              }
+            }
+          },
+          "4XX": {
+            "$ref": "#/components/responses/Error"
+          },
+          "5XX": {
+            "$ref": "#/components/responses/Error"
+          }
+        },
+        "x-dropshot-pagination": {
+          "required": []
+        }
+      }
+    },
+    "/v1/instances/{instance}/anti-affinity-groups": {
+      "get": {
+        "tags": [
+          "instances"
+        ],
+        "summary": "List anti-affinity groups containing instance",
+        "operationId": "instance_anti_affinity_group_list",
+        "parameters": [
+          {
+            "in": "query",
+            "name": "limit",
+            "description": "Maximum number of items returned by a single call",
+            "schema": {
+              "nullable": true,
+              "type": "integer",
+              "format": "uint32",
+              "minimum": 1
+            }
+          },
+          {
+            "in": "query",
+            "name": "page_token",
+            "description": "Token returned by previous call to retrieve the subsequent page",
+            "schema": {
+              "nullable": true,
+              "type": "string"
+            }
+          },
+          {
+            "in": "query",
+            "name": "project",
+            "description": "Name or ID of the project",
+            "schema": {
+              "$ref": "#/components/schemas/NameOrId"
+            }
+          },
+          {
+            "in": "query",
+            "name": "sort_by",
+            "schema": {
+              "$ref": "#/components/schemas/NameOrIdSortMode"
+            }
+          },
+          {
+            "in": "path",
+            "name": "instance",
+            "description": "Name or ID of the instance",
+            "required": true,
+            "schema": {
+              "$ref": "#/components/schemas/NameOrId"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "successful operation",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/AntiAffinityGroupResultsPage"
+                }
+              }
+            }
+          },
+          "4XX": {
+            "$ref": "#/components/responses/Error"
+          },
+          "5XX": {
+            "$ref": "#/components/responses/Error"
+          }
+        },
+        "x-dropshot-pagination": {
+          "required": []
+        }
+      }
+    },
     "/v1/instances/{instance}/disks": {
       "get": {
         "tags": [