diff --git a/packages/core/src/env-set/create-pool.ts b/packages/core/src/env-set/create-pool.ts
index 625b9dd12..a8e60283e 100644
--- a/packages/core/src/env-set/create-pool.ts
+++ b/packages/core/src/env-set/create-pool.ts
@@ -2,7 +2,7 @@ import { assert } from '@silverhand/essentials';
 import { createMockPool, createMockQueryResult, createPool, parseDsn } from 'slonik';
 import { createInterceptors } from 'slonik-interceptor-preset';
 
-const createPoolByEnv = async (databaseDsn: string, isTest: boolean) => {
+const createPoolByEnv = async (databaseDsn: string, isTest: boolean, poolSize?: number) => {
   // Database connection is disabled in unit test environment
   if (isTest) {
     return createMockPool({ query: async () => createMockQueryResult([]) });
@@ -12,7 +12,7 @@ const createPoolByEnv = async (databaseDsn: string, isTest: boolean) => {
 
   assert(parseDsn(databaseDsn).databaseName, new Error('Database name is required'));
 
-  return createPool(databaseDsn, { interceptors });
+  return createPool(databaseDsn, { interceptors, maximumPoolSize: poolSize });
 };
 
 export default createPoolByEnv;
diff --git a/packages/core/src/env-set/index.ts b/packages/core/src/env-set/index.ts
index 7d76b0c28..1bbe2d6c2 100644
--- a/packages/core/src/env-set/index.ts
+++ b/packages/core/src/env-set/index.ts
@@ -6,7 +6,7 @@ import type { DatabasePool } from 'slonik';
 import { createLogtoConfigLibrary } from '#src/libraries/logto-config.js';
 import { createLogtoConfigQueries } from '#src/queries/logto-config.js';
 
-import createPool from './create-pool.js';
+import createPoolByEnv from './create-pool.js';
 import loadOidcValues from './oidc.js';
 import { throwNotLoadedError } from './throw-errors.js';
 import { getTenantEndpoint } from './utils.js';
@@ -37,7 +37,7 @@ export class EnvSet {
     return this.values.dbUrl;
   }
 
-  static sharedPool = createPool(this.dbUrl, this.isTest);
+  static sharedPool = createPoolByEnv(this.dbUrl, this.isTest, this.values.databasePoolSize);
 
   #pool: Optional<DatabasePool>;
   #oidc: Optional<Awaited<ReturnType<typeof loadOidcValues>>>;
@@ -61,7 +61,11 @@ export class EnvSet {
   }
 
   async load() {
-    const pool = await createPool(this.databaseUrl, EnvSet.isTest);
+    const pool = await createPoolByEnv(
+      this.databaseUrl,
+      EnvSet.isTest,
+      EnvSet.values.databasePoolSize
+    );
 
     this.#pool = pool;
 
diff --git a/packages/core/src/tenants/index.ts b/packages/core/src/tenants/index.ts
index d79ece85f..af4cd2406 100644
--- a/packages/core/src/tenants/index.ts
+++ b/packages/core/src/tenants/index.ts
@@ -1,11 +1,13 @@
 import LRUCache from 'lru-cache';
 
+import { EnvSet } from '#src/env-set/index.js';
+
 import Tenant from './Tenant.js';
 
 export class TenantPool {
   protected cache = new LRUCache<string, Promise<Tenant>>({
-    max: 100,
-    dispose: async (entry) => {
+    max: EnvSet.values.tenantPoolSize,
+    dispose: (tenant) => {
       const tenant = await entry;
       void tenant.dispose();
     },
diff --git a/packages/shared/src/env/GlobalValues.ts b/packages/shared/src/env/GlobalValues.ts
index c61429473..7abddb1ef 100644
--- a/packages/shared/src/env/GlobalValues.ts
+++ b/packages/shared/src/env/GlobalValues.ts
@@ -98,6 +98,11 @@ export default class GlobalValues {
   public readonly trustProxyHeader = yes(getEnv('TRUST_PROXY_HEADER'));
   public readonly ignoreConnectorVersionCheck = yes(getEnv('IGNORE_CONNECTOR_VERSION_CHECK'));
 
+  /** Maximum number of tenants to keep in the tenant pool. */
+  public readonly tenantPoolSize = Number(getEnv('TENANT_POOL_SIZE', '100'));
+  /** Maximum number of clients to keep in a single database pool (i.e. per `Tenant` class). */
+  public readonly databasePoolSize = Number(getEnv('DATABASE_POOL_SIZE', '20'));
+
   public get dbUrl(): string {
     return this.databaseUrl;
   }