diff --git a/packages/cli/src/constructs/__tests__/telegram-alert-channel-codegen.spec.ts b/packages/cli/src/constructs/__tests__/telegram-alert-channel-codegen.spec.ts
new file mode 100644
index 00000000..07917fd9
--- /dev/null
+++ b/packages/cli/src/constructs/__tests__/telegram-alert-channel-codegen.spec.ts
@@ -0,0 +1,61 @@
+import { mkdtemp, readFile, rm } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import path from 'node:path'
+
+import { afterEach, beforeEach, describe, expect, it } from 'vitest'
+
+import { TelegramAlertChannelCodegen, type TelegramAlertChannelResource } from '../telegram-alert-channel-codegen.js'
+import { Context } from '../internal/codegen/index.js'
+import { Program } from '../../sourcegen/index.js'
+
+describe('TelegramAlertChannelCodegen', () => {
+  let rootDirectory: string
+
+  beforeEach(async () => {
+    rootDirectory = await mkdtemp(path.join(tmpdir(), 'telegram-alert-channel-codegen-'))
+  })
+
+  afterEach(async () => {
+    await rm(rootDirectory, { recursive: true, force: true })
+  })
+
+  it('preserves the message thread ID when exporting a Telegram alert channel', async () => {
+    const program = new Program({
+      rootDirectory,
+      constructFileSuffix: '.check',
+      specFileSuffix: '.spec',
+      language: 'typescript',
+    })
+    const codegen = new TelegramAlertChannelCodegen(program)
+    const context = new Context()
+    const resource: TelegramAlertChannelResource = {
+      id: 123,
+      type: 'WEBHOOK',
+      config: {
+        name: 'Telegram topic',
+        webhookType: 'WEBHOOK_TELEGRAM',
+        url: 'https://api.telegram.org/bot123456:ABC/sendMessage',
+        method: 'POST',
+        headers: [],
+        template: 'chat_id=-701234567&message_thread_id=42&parse_mode=HTML&text=test',
+      },
+      sendRecovery: true,
+      sendFailure: true,
+      sendDegraded: false,
+      sslExpiry: false,
+      sslExpiryThreshold: 30,
+    }
+
+    codegen.prepare('telegram-topic', resource, context)
+    codegen.gencode('telegram-topic', resource, context)
+    await program.realize()
+
+    const [filePath] = program.paths
+    if (filePath === undefined) {
+      throw new Error('Codegen did not register a generated file')
+    }
+    const source = await readFile(filePath, 'utf8')
+
+    expect(source).toContain(`messageThreadId: '42'`)
+  })
+})
diff --git a/packages/cli/src/constructs/__tests__/telegram-alert-channel.spec.ts b/packages/cli/src/constructs/__tests__/telegram-alert-channel.spec.ts
new file mode 100644
index 00000000..5557a6b7
--- /dev/null
+++ b/packages/cli/src/constructs/__tests__/telegram-alert-channel.spec.ts
@@ -0,0 +1,47 @@
+import { beforeEach, describe, expect, it } from 'vitest'
+
+import { Project } from '../project.js'
+import { Session } from '../session.js'
+import { TelegramAlertChannel } from '../telegram-alert-channel.js'
+
+describe('TelegramAlertChannel', () => {
+  beforeEach(() => {
+    Session.project = new Project('project-id', {
+      name: 'Test Project',
+      repoUrl: 'https://github.com/checkly/checkly-cli',
+    })
+  })
+
+  it('includes the message thread ID in the Telegram request template', () => {
+    const channel = new TelegramAlertChannel('telegram-topic', {
+      name: 'Telegram topic',
+      apiKey: '123456:ABC',
+      chatId: '-701234567',
+      messageThreadId: '42',
+      payload: 'test',
+    })
+
+    expect(channel.synthesize()).toMatchObject({
+      type: 'WEBHOOK',
+      config: {
+        webhookType: 'WEBHOOK_TELEGRAM',
+        template: 'chat_id=-701234567&message_thread_id=42&parse_mode=HTML&text=test',
+      },
+    })
+  })
+
+  it('keeps the existing template shape when no message thread ID is configured', () => {
+    const channel = new TelegramAlertChannel('telegram-chat', {
+      name: 'Telegram chat',
+      apiKey: '123456:ABC',
+      chatId: '-701234567',
+      payload: 'test',
+    })
+
+    expect(channel.synthesize()).toMatchObject({
+      config: {
+        template: 'chat_id=-701234567&parse_mode=HTML&text=test',
+      },
+    })
+  })
+})
diff --git a/packages/cli/src/constructs/telegram-alert-channel-codegen.ts b/packages/cli/src/constructs/telegram-alert-channel-codegen.ts
index d499625d..f2580d0d 100644
--- a/packages/cli/src/constructs/telegram-alert-channel-codegen.ts
+++ b/packages/cli/src/constructs/telegram-alert-channel-codegen.ts
@@ -21,6 +21,7 @@ function apiKeyFromUrl (url: string): string | undefined {
 
 interface TemplateValues {
   chatId?: string
+  messageThreadId?: string
   text?: string
 }
 
@@ -37,6 +38,7 @@ function parseTemplate (template: string): TemplateValues {
 
   return {
     chatId: singleValue('chat_id'),
+    messageThreadId: singleValue('message_thread_id'),
     text: singleValue('text'),
   }
 }
@@ -110,13 +112,17 @@ export class TelegramAlertChannelCodegen extends Codegen<TelegramAlertChannelRes
             }
 
             if (config.template) {
-              const { chatId, text } = parseTemplate(config.template)
+              const { chatId, messageThreadId, text } = parseTemplate(config.template)
               if (chatId) {
                 builder.string('chatId', chatId)
               } else {
                 throw new Error(`Failed to extract Telegram Chat ID from webhook template: ${config.template}`)
               }
 
+              if (messageThreadId) {
+                builder.string('messageThreadId', messageThreadId)
+              }
+
               if (text) {
                 if (text !== TelegramAlertChannel.DEFAULT_PAYLOAD) {
                   builder.string('payload', text)
diff --git a/packages/cli/src/constructs/telegram-alert-channel.ts b/packages/cli/src/constructs/telegram-alert-channel.ts
index 2ff0f96b..29af77b2 100644
--- a/packages/cli/src/constructs/telegram-alert-channel.ts
+++ b/packages/cli/src/constructs/telegram-alert-channel.ts
@@ -16,6 +16,11 @@ export interface TelegramAlertChannelProps extends AlertChannelProps {
    * {@link https://www.checklyhq.com/docs/integrations/alerts/telegram/}
    */
   apiKey: string
+  /**
+   * The optional message thread ID of a Telegram forum topic.
+   * {@link https://core.telegram.org/bots/api#sendmessage}
+   */
+  messageThreadId?: string
   /**
    * An optional custom payload. If not given,
    * `TelegramAlertChannel.DEFAULT_PAYLOAD` will be used.
@@ -57,9 +62,12 @@ Tags: {{#each TAGS}} <i><b>{{this}}</b></i> {{#unless @last}},{{/unless}} {{/eac
     this.webhookType = 'WEBHOOK_TELEGRAM'
     this.method = 'POST'
     const payload = props.payload ?? TelegramAlertChannel.DEFAULT_PAYLOAD
+    const messageThreadPart = props.messageThreadId
+      ? `&message_thread_id=${props.messageThreadId}`
+      : ''
     // For historical reasons the payload is not escaped even though it
     // should be.
-    this.template = `chat_id=${props.chatId}&parse_mode=HTML&text=${payload}`
+    this.template = `chat_id=${props.chatId}${messageThreadPart}&parse_mode=HTML&text=${payload}`
     this.url = `https://api.telegram.org/bot${props.apiKey}/sendMessage`
   }