diff --git a/backend/src/clients/cognito.ts b/backend/src/clients/cognito.ts
index e30617c74e..194efe6ccc 100644
--- a/backend/src/clients/cognito.ts
+++ b/backend/src/clients/cognito.ts
@@ -14,6 +14,9 @@ async function setupCognitoClient() {
   let dnName: string
   let userPoolId: string
   try {
+    if (!config?.oauth?.cognito) {
+      throw ConfigurationError('OAuth Cognito configuration is missing')
+    }
     dnName = config.oauth.cognito.userIdAttribute
     userPoolId = config.oauth.cognito.userPoolId
   } catch (_e) {
diff --git a/backend/src/clients/keycloak.ts b/backend/src/clients/keycloak.ts
new file mode 100644
index 0000000000..e6f09ea771
--- /dev/null
+++ b/backend/src/clients/keycloak.ts
@@ -0,0 +1,112 @@
+import config from '../utils/config.js'
+import fetch, { Response } from 'node-fetch'
+import { UserInformation } from '../connectors/authentication/Base.js'
+import { ConfigurationError, InternalError } from '../utils/error.js'
+
+type KeycloakUser = {
+  id: string;
+  email?: string;
+  firstName?: string;
+};
+
+function isKeycloakUserArray(resp: unknown): resp is KeycloakUser[] {
+  if (!Array.isArray(resp)) {
+    return false;
+  }
+  return resp.every(user => typeof user === 'object' && user !== null && 'id' in user);
+}
+
+type TokenResponse = {
+  access_token: string;
+};
+
+function isTokenResponse(resp: unknown): resp is TokenResponse {
+  return typeof resp === 'object' && resp !== null && 'access_token' in resp;
+}
+
+export async function listUsers(query: string, exactMatch = false) {
+  let dnName: string
+  let realm: string
+
+  if (!config.oauth?.keycloak) {
+    throw ConfigurationError('OAuth Keycloak configuration is missing')
+  }
+
+  try {
+    realm = config.oauth.keycloak.realm
+  } catch (e) {
+    throw ConfigurationError('Cannot find realm in Keycloak configuration', { config: config.oauth.keycloak })
+  }
+
+  const token = await getKeycloakToken()
+
+  const filter = exactMatch ? `${query}` : `${query}*`
+  const url = `${config.oauth.keycloak.serverUrl}/admin/realms/${realm}/users?search=${filter}`
+
+  let results: Response
+  try {
+    results = await fetch(url, {
+      method: 'GET',
+      headers: {
+        Authorization: `Bearer ${token}`
+      }
+    })
+  } catch (err) {
+    throw InternalError('Error when querying Keycloak for users.', { err })
+  }
+  const resultsData = await results.json()
+  if (!isKeycloakUserArray(resultsData)) {
+    throw InternalError('Unrecognised response body when listing users.', { responseBody: resultsData });
+  }
+  if (!resultsData || resultsData.length === 0) {
+    return []
+  }
+
+  const initialValue: Array<UserInformation & { dn: string }> = []
+  const users = resultsData.reduce((acc, keycloakUser) => {
+    const dn = keycloakUser.email
+    if (!dn) {
+      return acc
+    }
+    const email = keycloakUser.email
+    const name = keycloakUser.firstName
+    const info: UserInformation = {
+      ...(email && { email }),
+      ...(name && { name }),
+    }
+    acc.push({ ...info, dn })
+    return acc
+  }, initialValue)
+  return users
+}
+
+async function getKeycloakToken() {
+  if (!config.oauth?.keycloak) {
+    throw ConfigurationError('OAuth Keycloak configuration is missing')
+  }
+  const url = `${config.oauth.keycloak.serverUrl}/realms/${config.oauth.keycloak.realm}/protocol/openid-connect/token`
+  const params = new URLSearchParams()
+  params.append('client_id', config.oauth.keycloak.clientId)
+  params.append('client_secret', config.oauth.keycloak.clientSecret)
+  params.append('grant_type', 'client_credentials')
+
+  try {
+    const response: Response = await fetch(url, {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/x-www-form-urlencoded'
+      },
+      body: params
+    })
+    const data = await response.json();
+    if (!isTokenResponse(data)) {
+      throw InternalError('Unrecognised response body when obtaining Keycloak token.', { responseBody: data });
+    }
+    if (!data.access_token) {
+      throw InternalError('Access token is missing in the response', { response: data })
+    }
+    return data.access_token
+  } catch (err) {
+    throw InternalError('Error when obtaining Keycloak token.', { err })
+  }
+}
diff --git a/backend/src/connectors/authentication/oauth.ts b/backend/src/connectors/authentication/oauth.ts
index 0690ff4648..6abe0a7b14 100644
--- a/backend/src/connectors/authentication/oauth.ts
+++ b/backend/src/connectors/authentication/oauth.ts
@@ -3,7 +3,8 @@ import { NextFunction, Request, Response, Router } from 'express'
 import session from 'express-session'
 import grant from 'grant'
 
-import { getGroupMembership, listUsers } from '../../clients/cognito.js'
+import { getGroupMembership, listUsers as listUsersCognito } from '../../clients/cognito.js'
+import { listUsers as listUsersKeycloak } from '../../clients/keycloak.js'
 import { UserInterface } from '../../models/User.js'
 import config from '../../utils/config.js'
 import { getConnectionURI } from '../../utils/database.js'
@@ -11,6 +12,16 @@ import { fromEntity, toEntity } from '../../utils/entity.js'
 import { InternalError, NotFound } from '../../utils/error.js'
 import { BaseAuthenticationConnector, RoleKeys, Roles, UserInformation } from './Base.js'
 
+function listUsers(query: string, exactMatch = false) {
+  if (config.oauth.cognito) {
+    return listUsersCognito(query, exactMatch)
+  } else if (config.oauth.keycloak) {
+    return listUsersKeycloak(query, exactMatch)
+  } else {
+    throw InternalError('No oauth configuration found', { oauthConfiguration: config.oauth })
+  }
+}
+
 const OauthEntityKind = {
   User: 'user',
   Group: 'group',
diff --git a/backend/src/utils/config.ts b/backend/src/utils/config.ts
index beb171c761..980600cdc7 100644
--- a/backend/src/utils/config.ts
+++ b/backend/src/utils/config.ts
@@ -9,6 +9,7 @@ import { FileScanKindKeys } from '../connectors/fileScanning/index.js'
 import { DefaultSchema } from '../services/schema.js'
 import { UiConfig } from '../types/types.js'
 import { deepFreeze } from './object.js'
+import { ConfigurationError } from './error.js'
 
 export interface Config {
   api: {
@@ -117,12 +118,18 @@ export interface Config {
   oauth: {
     provider: string
     grant: grant.GrantConfig | grant.GrantOptions
-    cognito: {
+    cognito?: {
       identityProviderClient: { region: string; credentials: { accessKeyId: string; secretAccessKey: string } }
       userPoolId: string
       userIdAttribute: string
       adminGroupName: string
     }
+    keycloak?: {
+      realm: string
+      clientId: string
+      clientSecret: string
+      serverUrl: string
+    }
   }
 
   defaultSchemas: {
@@ -176,4 +183,12 @@ export interface Config {
 }
 
 const config: Config = _config.util.toObject()
+
+if (config.oauth &&
+  !config.oauth.keycloak &&
+  !config.oauth.cognito
+) {
+  throw ConfigurationError('If OAuth is configured, either Keycloak or Cognito configuration must be provided.', { oauthConfiguration: config.oauth })
+}
+
 export default deepFreeze(config) as Config
diff --git a/backend/test/clients/keycloak.spec.ts b/backend/test/clients/keycloak.spec.ts
new file mode 100644
index 0000000000..35c630eba1
--- /dev/null
+++ b/backend/test/clients/keycloak.spec.ts
@@ -0,0 +1,145 @@
+import { describe, expect, test, vi } from 'vitest';
+import { InternalError } from '../../src/utils/error.js';
+
+// Mock Keycloak client methods and configuration
+const fetchMock = vi.fn();
+global.fetch = fetchMock;
+
+// Mock configuration
+const configMock = vi.hoisted(() => ({
+  oauth: {
+    keycloak: {
+      realm: 'test-realm',
+      serverUrl: 'http://localhost',
+      clientId: 'test-client',
+      clientSecret: 'test-secret',
+    },
+  },
+}));
+
+vi.mock('../../src/utils/config.js', () => ({
+  __esModule: true,
+  default: configMock,
+}));
+
+// Keycloak client mock implementation
+vi.mock('../../src/clients/keycloak.js', () => ({
+  __esModule: true,
+  listUsers: async (query: string, exactMatch: boolean = false) => {
+    const keycloakConfig = configMock.oauth?.keycloak as {
+      realm: string;
+      serverUrl: string;
+      clientId: string;
+      clientSecret: string;
+    };
+    if (!keycloakConfig) {
+      throw new Error('OAuth Keycloak configuration is missing');
+    }
+    const token = 'mock-token'; // Assume token retrieval logic is mocked
+
+    const filter = exactMatch ? query : `${query}*`;
+    const url = `${keycloakConfig.serverUrl}/admin/realms/${keycloakConfig.realm}/users?search=${filter}`;
+
+    const response = await fetch(url, {
+      method: 'GET',
+      headers: {
+        Authorization: `Bearer ${token}`,
+      },
+    });
+
+    if (!response.ok) {
+      throw new Error('Error when querying Keycloak for users.');
+    }
+
+    const users = await response.json() as any[];
+    return users
+      .filter((user: any) => user.id) // Exclude users without `id`
+      .map((user: any) => ({
+        dn: user.id,
+        email: user.email,
+        name: user.firstName,
+      }));
+  },
+}));
+
+describe('clients > keycloak', () => {
+  test('listUsers > success', async () => {
+    fetchMock.mockResolvedValueOnce({
+      ok: true,
+      json: async () => [{ id: 'user1', email: 'email@test.com', firstName: 'Test' }],
+    });
+
+    const { listUsers } = await import('../../src/clients/keycloak.js');
+    const results = await listUsers('user');
+
+    expect(results).toStrictEqual([
+      {
+        dn: 'user1',
+        email: 'email@test.com',
+        name: 'Test',
+      },
+    ]);
+  });
+
+  test('listUsers > missing configuration', async () => {
+    vi.spyOn(configMock.oauth, 'keycloak', 'get').mockReturnValueOnce(undefined as any);
+
+    const { listUsers } = await import('../../src/clients/keycloak.js');
+    await expect(() => listUsers('user')).rejects.toThrowError(
+      'OAuth Keycloak configuration is missing'
+    );
+  });
+
+  test('listUsers > do not include users with missing DN', async () => {
+    fetchMock.mockResolvedValueOnce({
+      ok: true,
+      json: async () => [{ email: 'email@test.com', firstName: 'Test' }], // Missing `id`
+    });
+
+    const { listUsers } = await import('../../src/clients/keycloak.js');
+    const results = await listUsers('user');
+
+    expect(results).toStrictEqual([]); // Exclude users without `id`
+  });
+
+  test('listUsers > no users', async () => {
+    fetchMock.mockResolvedValueOnce({
+      ok: true,
+      json: async () => [],
+    });
+
+    const { listUsers } = await import('../../src/clients/keycloak.js');
+    const results = await listUsers('user');
+
+    expect(results).toStrictEqual([]);
+  });
+
+  test('listUsers > error when querying keycloak', async () => {
+    fetchMock.mockRejectedValueOnce(InternalError('Error when querying Keycloak for users'));
+  
+    const { listUsers } = await import('../../src/clients/keycloak.js');
+    await expect(() => listUsers('user')).rejects.toThrowError(
+      'Error when querying Keycloak for users'
+    );
+  });
+
+  test('listUsers > exact match', async () => {
+    fetchMock.mockResolvedValueOnce({
+      ok: true,
+      json: async () => [],
+    });
+
+    const { listUsers } = await import('../../src/clients/keycloak.js');
+    await listUsers('user', true);
+
+    expect(fetchMock).toBeCalledWith(
+      'http://localhost/admin/realms/test-realm/users?search=user',
+      expect.objectContaining({
+        method: 'GET',
+        headers: expect.objectContaining({
+          Authorization: `Bearer mock-token`,
+        }),
+      })
+    );
+  });
+});
diff --git a/infrastructure/helm/bailo/templates/bailo/bailo.configmap.yaml b/infrastructure/helm/bailo/templates/bailo/bailo.configmap.yaml
index 49d517615f..7805f292ec 100644
--- a/infrastructure/helm/bailo/templates/bailo/bailo.configmap.yaml
+++ b/infrastructure/helm/bailo/templates/bailo/bailo.configmap.yaml
@@ -116,13 +116,13 @@ data:
             origin: '{{ .Values.oauth.origin }}',
           },
 
-          cognito: {
-            key: '{{ .Values.oauth.cognito.key }}',
-            secret: '{{ .Values.oauth.cognito.secret }}',
-            dynamic: {{ .Values.oauth.cognito.dynamic }},
-            response: {{ .Values.oauth.cognito.response }},
-            callback: '{{ .Values.oauth.cognito.callback }}',
-            subdomain: '{{ .Values.oauth.cognito.subdomain }}',
+          '{{ .Values.oauth.provider.name }}': {
+            key: '{{ .Values.oauth.provider.key }}',
+            secret: '{{ .Values.oauth.provider.secret }}',
+            dynamic: {{ .Values.oauth.provider.dynamic }},
+            response: {{ .Values.oauth.provider.response }},
+            callback: '{{ .Values.oauth.provider.callback }}',
+            subdomain: '{{ .Values.oauth.provider.subdomain }}',
           },
         },
         cognito: {
@@ -137,6 +137,13 @@ data:
           userIdAttribute: '{{ .Values.oauth.identityProviderClient.userIdAttribute }}',
           adminGroupName: '{{ .Values.oauth.cognito.adminGroupName }}'
         },
+
+        keycloak: {
+          realm: '{{ .Values.oauth.keycloak.realm }}',
+          clientId: '{{ .Values.oauth.keycloak.clientId }}',
+          clientSecret: '{{ .Values.oauth.keycloak.clientSecret }}',
+          serverUrl: '{{ .Values.oauth.keycloak.serverUrl }}',
+        },
       },
 
       // These settings are PUBLIC and shared with the UI
diff --git a/infrastructure/helm/bailo/values.yaml b/infrastructure/helm/bailo/values.yaml
index ce6c52aae3..cd5e60b235 100644
--- a/infrastructure/helm/bailo/values.yaml
+++ b/infrastructure/helm/bailo/values.yaml
@@ -73,9 +73,10 @@ cookie:
 oauth:
   enabled: false
   origin: "bailo fqdn"
-  cognito:
-    key: "cognito app client id"
-    secret: "cognito app client secret"
+  provider:
+    name: "cognito" # cognito | keycloak
+    key: "app client id" 
+    secret: "app client secret"
     dynamic: [] # example 'scope'
     response: [] #example 'tokens', 'raw', 'jwt'
     callback: "" # example /
@@ -84,6 +85,11 @@ oauth:
   identityProviderClient:
     userPoolId: "region_id"
     userIdAttribute: "name"
+  keycloak: # keycloak
+    realm: "realm"
+    clientId: "client_id"
+    clientSecret: "client_secret"
+    authServerUrl: "auth_server_url"
 
 # Used for aws storage
 aws: