diff --git a/server/migrations/20251218223224-add-grant-id-to-oauth-models.js b/server/migrations/20251218223224-add-grant-id-to-oauth-models.js
new file mode 100644
index 0000000000..332a29b871
--- /dev/null
+++ b/server/migrations/20251218223224-add-grant-id-to-oauth-models.js
@@ -0,0 +1,61 @@
+"use strict";
+
+/** @type {import("sequelize-cli").Migration} */
+module.exports = {
+  async up(queryInterface, Sequelize) {
+    await queryInterface.sequelize.transaction(async (transaction) => {
+      await queryInterface.addColumn(
+        "oauth_authentications",
+        "grantId",
+        {
+          type: Sequelize.UUID,
+          allowNull: true,
+        },
+        { transaction }
+      );
+
+      await queryInterface.addColumn(
+        "oauth_authorization_codes",
+        "grantId",
+        {
+          type: Sequelize.UUID,
+          allowNull: true,
+        },
+        { transaction }
+      );
+
+      await queryInterface.addIndex("oauth_authentications", ["grantId"], {
+        transaction,
+      });
+
+      await queryInterface.addIndex("oauth_authorization_codes", ["grantId"], {
+        transaction,
+      });
+    });
+  },
+
+  async down(queryInterface, Sequelize) {
+    await queryInterface.sequelize.transaction(async (transaction) => {
+      await queryInterface.removeIndex("oauth_authentications", ["grantId"], {
+        transaction,
+      });
+      await queryInterface.removeIndex(
+        "oauth_authorization_codes",
+        ["grantId"],
+        {
+          transaction,
+        }
+      );
+      await queryInterface.removeColumn("oauth_authentications", "grantId", {
+        transaction,
+      });
+      await queryInterface.removeColumn(
+        "oauth_authorization_codes",
+        "grantId",
+        {
+          transaction,
+        }
+      );
+    });
+  },
+};
diff --git a/server/models/oauth/OAuthAuthentication.ts b/server/models/oauth/OAuthAuthentication.ts
index 8d81d8b03a..049112d962 100644
--- a/server/models/oauth/OAuthAuthentication.ts
+++ b/server/models/oauth/OAuthAuthentication.ts
@@ -74,6 +74,14 @@ class OAuthAuthentication extends ParanoidModel<
   @Column
   refreshTokenExpiresAt: Date;
 
+  /**
+   * The ID of the grant that this authentication belongs to. Used for
+   * refresh token rotation and revocation of all tokens in a grant.
+   */
+  @Column(DataType.UUID)
+  @SkipChangeset
+  grantId: string | null;
+
   /** A list of scopes that this authentication has access to */
   @Matches(/[\/\.\w\s]*/, {
     each: true,
diff --git a/server/models/oauth/OAuthAuthorizationCode.ts b/server/models/oauth/OAuthAuthorizationCode.ts
index d6c742759a..890b979fb3 100644
--- a/server/models/oauth/OAuthAuthorizationCode.ts
+++ b/server/models/oauth/OAuthAuthorizationCode.ts
@@ -48,6 +48,14 @@ class OAuthAuthorizationCode extends IdModel<
   @SkipChangeset
   codeChallengeMethod?: string;
 
+  /**
+   * The ID of the grant that this authorization code belongs to. Used for
+   * refresh token rotation and revocation of all tokens in a grant.
+   */
+  @Column(DataType.UUID)
+  @SkipChangeset
+  grantId: string | null;
+
   /** A list of scopes that this authorization code has access to */
   @Matches(/[\/\.\w\s]*/, {
     each: true,
diff --git a/server/routes/oauth/index.test.ts b/server/routes/oauth/index.test.ts
index d8d9427f64..fbde594d14 100644
--- a/server/routes/oauth/index.test.ts
+++ b/server/routes/oauth/index.test.ts
@@ -1,5 +1,6 @@
+import crypto from "crypto";
 import { Scope } from "@shared/types";
-import { OAuthAuthentication } from "@server/models";
+import { OAuthAuthentication, OAuthAuthorizationCode } from "@server/models";
 import {
   buildOAuthAuthentication,
   buildOAuthClient,
@@ -230,5 +231,125 @@ describe("#oauth.token", () => {
         "Missing client_secret for confidential client"
       );
     });
+
+    it("should revoke all tokens in a grant when a refresh token is reused", async () => {
+      const user = await buildUser();
+      const client = await buildOAuthClient({
+        teamId: user.teamId,
+        clientType: "confidential",
+      });
+      const grantId = crypto.randomUUID();
+
+      // Create initial authentication
+      const auth1 = await buildOAuthAuthentication({
+        user,
+        scope: [Scope.Read],
+        oauthClientId: client.id,
+        grantId,
+      });
+
+      // Use the refresh token once (rotation)
+      const res1 = await server.post("/oauth/token", {
+        headers: {
+          "Content-Type": "application/x-www-form-urlencoded",
+        },
+        body: toFormData({
+          grant_type: "refresh_token",
+          refresh_token: auth1.refreshToken,
+          client_id: client.clientId,
+          client_secret: client.clientSecret,
+        }),
+      });
+      expect(res1.status).toEqual(200);
+      const body1 = await res1.json();
+      const auth2RefreshToken = body1.refresh_token;
+
+      // Create an unrelated authentication
+      const otherAuth = await buildOAuthAuthentication({
+        user,
+        scope: [Scope.Read],
+      });
+
+      // Use the OLD refresh token again (reuse detection)
+      const res2 = await server.post("/oauth/token", {
+        headers: {
+          "Content-Type": "application/x-www-form-urlencoded",
+        },
+        body: toFormData({
+          grant_type: "refresh_token",
+          refresh_token: auth1.refreshToken,
+          client_id: client.clientId,
+          client_secret: client.clientSecret,
+        }),
+      });
+
+      // The request should fail
+      expect(res2.status).toEqual(400);
+
+      // All tokens in the grant should be revoked
+      const foundAuth1 = await OAuthAuthentication.findByPk(auth1.id, {
+        paranoid: false,
+      });
+      const foundAuth2 =
+        await OAuthAuthentication.findByRefreshToken(auth2RefreshToken);
+      const foundOtherAuth = await OAuthAuthentication.findByPk(otherAuth.id);
+
+      expect(foundAuth1?.deletedAt).toBeTruthy();
+      expect(foundAuth2).toBeNull();
+      expect(foundOtherAuth).not.toBeNull();
+    });
+
+    it("should revoke associated authorization codes when reuse is detected", async () => {
+      const user = await buildUser();
+      const client = await buildOAuthClient({ teamId: user.teamId });
+      const grantId = crypto.randomUUID();
+
+      const auth = await buildOAuthAuthentication({
+        user,
+        scope: [Scope.Read],
+        oauthClientId: client.id,
+        grantId,
+      });
+
+      const code = await OAuthAuthorizationCode.create({
+        authorizationCodeHash: "hash",
+        scope: [Scope.Read],
+        redirectUri: client.redirectUris[0],
+        oauthClientId: client.id,
+        userId: user.id,
+        expiresAt: new Date(Date.now() + 10000),
+        grantId,
+      });
+
+      // Use the refresh token once (rotation)
+      await server.post("/oauth/token", {
+        headers: {
+          "Content-Type": "application/x-www-form-urlencoded",
+        },
+        body: toFormData({
+          grant_type: "refresh_token",
+          refresh_token: auth.refreshToken,
+          client_id: client.clientId,
+          client_secret: client.clientSecret,
+        }),
+      });
+
+      // Use the OLD refresh token again (reuse detection)
+      await server.post("/oauth/token", {
+        headers: {
+          "Content-Type": "application/x-www-form-urlencoded",
+        },
+        body: toFormData({
+          grant_type: "refresh_token",
+          refresh_token: auth.refreshToken,
+          client_id: client.clientId,
+          client_secret: client.clientSecret,
+        }),
+      });
+
+      // The authorization code should be gone
+      const foundCode = await OAuthAuthorizationCode.findByPk(code.id);
+      expect(foundCode).toBeNull();
+    });
   });
 });
diff --git a/server/test/factories.ts b/server/test/factories.ts
index e17a22233c..2f5ce5e1ff 100644
--- a/server/test/factories.ts
+++ b/server/test/factories.ts
@@ -797,10 +797,12 @@ export async function buildOAuthAuthentication({
   oauthClientId,
   user,
   scope,
+  grantId,
 }: {
   oauthClientId?: string;
   user: User;
   scope: string[];
+  grantId?: string;
 }) {
   const oauthClient = oauthClientId
     ? await OAuthClient.findByPk(oauthClientId, { rejectOnEmpty: true })
@@ -836,6 +838,7 @@ export async function buildOAuthAuthentication({
     refreshTokenHash: hash(refreshToken),
     refreshTokenExpiresAt: new Date(Date.now() + 1000 * 60 * 60 * 24 * 30),
     scope,
+    grantId,
   });
 }
 
diff --git a/server/utils/oauth/OAuthInterface.ts b/server/utils/oauth/OAuthInterface.ts
index 7f9e3830af..549c765982 100644
--- a/server/utils/oauth/OAuthInterface.ts
+++ b/server/utils/oauth/OAuthInterface.ts
@@ -2,6 +2,7 @@ import crypto from "crypto";
 import {
   RefreshTokenModel,
   AuthorizationCodeModel,
+  User as OAuthUser,
 } from "@node-oauth/oauth2-server";
 import { Required } from "utility-types";
 import { Scope } from "@shared/types";
@@ -21,6 +22,14 @@ interface Config {
   grants: string[];
 }
 
+/**
+ * An extension of the OAuth2Server User type that includes a grantId for
+ * session tracking.
+ */
+interface GrantUser extends OAuthUser {
+  grantId?: string;
+}
+
 /**
  * This interface is used by the OAuth2Server library to handle OAuth2
  * authentication and authorization flows. See the library's documentation:
@@ -40,24 +49,45 @@ export const OAuthInterface: RefreshTokenModel &
   /** Supported grant types */
   grants: ["authorization_code", "refresh_token"],
 
+  /**
+   * Generates a new access token.
+   *
+   * @returns The generated access token.
+   */
   async generateAccessToken() {
     return `${OAuthAuthentication.accessTokenPrefix}${crypto
       .randomBytes(32)
       .toString("hex")}`;
   },
 
+  /**
+   * Generates a new refresh token.
+   *
+   * @returns The generated refresh token.
+   */
   async generateRefreshToken() {
     return `${OAuthAuthentication.refreshTokenPrefix}${crypto
       .randomBytes(32)
       .toString("hex")}`;
   },
 
+  /**
+   * Generates a new authorization code.
+   *
+   * @returns The generated authorization code.
+   */
   async generateAuthorizationCode() {
     return `${OAuthAuthorizationCode.authorizationCodePrefix}${crypto
       .randomBytes(32)
       .toString("hex")}`;
   },
 
+  /**
+   * Retrieves an access token by its value.
+   *
+   * @param accessToken The access token to retrieve.
+   * @returns The access token if found, false otherwise.
+   */
   async getAccessToken(accessToken: string) {
     const authentication =
       await OAuthAuthentication.findByAccessToken(accessToken);
@@ -77,13 +107,47 @@ export const OAuthInterface: RefreshTokenModel &
     };
   },
 
+  /**
+   * Retrieves a refresh token by its value, with reuse detection.
+   *
+   * @param refreshToken The refresh token to retrieve.
+   * @returns The refresh token if found, false otherwise.
+   */
   async getRefreshToken(refreshToken: string) {
-    const authentication =
+    let authentication =
       await OAuthAuthentication.findByRefreshToken(refreshToken);
+
     if (!authentication) {
+      // If the refresh token is not found, it may have already been used or
+      // revoked. In this case we perform reuse detection as recommended by RFC 9700.
+      authentication = await OAuthAuthentication.findOne({
+        where: {
+          refreshTokenHash: hash(refreshToken),
+        },
+        paranoid: false,
+      });
+
+      if (authentication?.grantId) {
+        await Promise.all([
+          OAuthAuthentication.destroy({
+            where: {
+              grantId: authentication.grantId,
+            },
+          }),
+          OAuthAuthorizationCode.destroy({
+            where: {
+              grantId: authentication.grantId,
+            },
+          }),
+        ]);
+      }
+
       return false;
     }
 
+    const user = authentication.user;
+    Object.assign(user, { grantId: authentication.grantId });
+
     return {
       refreshToken,
       refreshTokenExpiresAt: authentication.refreshTokenExpiresAt,
@@ -92,10 +156,16 @@ export const OAuthInterface: RefreshTokenModel &
         id: authentication.oauthClient.clientId,
         grants: this.grants,
       },
-      user: authentication.user,
+      user,
     };
   },
 
+  /**
+   * Retrieves an authorization code by its value.
+   *
+   * @param authorizationCode The authorization code to retrieve.
+   * @returns The authorization code if found, false otherwise.
+   */
   async getAuthorizationCode(authorizationCode) {
     const code = await OAuthAuthorizationCode.findByCode(authorizationCode);
     if (!code) {
@@ -107,6 +177,9 @@ export const OAuthInterface: RefreshTokenModel &
       return false;
     }
 
+    const user = code.user;
+    Object.assign(user, { grantId: code.grantId });
+
     return {
       authorizationCode,
       expiresAt: code.expiresAt,
@@ -118,10 +191,17 @@ export const OAuthInterface: RefreshTokenModel &
         id: oauthClient.clientId,
         grants: this.grants,
       },
-      user: code.user,
+      user,
     };
   },
 
+  /**
+   * Retrieves a client by its ID and secret.
+   *
+   * @param clientId The client ID.
+   * @param clientSecret The client secret.
+   * @returns The client if found and valid, false otherwise.
+   */
   async getClient(clientId: string, clientSecret?: string) {
     const client = await OAuthClient.findByClientId(clientId);
     if (!client) {
@@ -141,6 +221,14 @@ export const OAuthInterface: RefreshTokenModel &
     };
   },
 
+  /**
+   * Saves an access and refresh token.
+   *
+   * @param token The token object to save.
+   * @param client The client that requested the token.
+   * @param user The user that authorized the token.
+   * @returns The saved token.
+   */
   async saveToken(token, client, user) {
     const {
       accessToken,
@@ -159,6 +247,7 @@ export const OAuthInterface: RefreshTokenModel &
       scope: token.scope,
       oauthClientId: client.databaseId,
       userId: user.id,
+      grantId: (user as GrantUser).grantId || crypto.randomUUID(),
     });
 
     return {
@@ -175,6 +264,14 @@ export const OAuthInterface: RefreshTokenModel &
     };
   },
 
+  /**
+   * Saves an authorization code.
+   *
+   * @param code The authorization code object to save.
+   * @param client The client that requested the code.
+   * @param user The user that authorized the code.
+   * @returns The saved authorization code.
+   */
   async saveAuthorizationCode(code, client, user) {
     const {
       authorizationCode,
@@ -194,6 +291,7 @@ export const OAuthInterface: RefreshTokenModel &
       codeChallengeMethod,
       oauthClientId: client.databaseId,
       userId: user.id,
+      grantId: (user as GrantUser).grantId || crypto.randomUUID(),
     });
 
     return {
@@ -209,6 +307,12 @@ export const OAuthInterface: RefreshTokenModel &
     };
   },
 
+  /**
+   * Revokes a refresh token.
+   *
+   * @param token The token object containing the refresh token to revoke.
+   * @returns True if the token was revoked, false otherwise.
+   */
   async revokeToken(token) {
     const auth = await OAuthAuthentication.findByRefreshToken(
       token.refreshToken
@@ -220,6 +324,12 @@ export const OAuthInterface: RefreshTokenModel &
     return false;
   },
 
+  /**
+   * Revokes an authorization code.
+   *
+   * @param code The authorization code object to revoke.
+   * @returns True if the code was revoked, false otherwise.
+   */
   async revokeAuthorizationCode(code) {
     const authCode = await OAuthAuthorizationCode.findByCode(
       code.authorizationCode