diff --git a/docs/Ake.md b/docs/Ake.md
index e6004dd..37fdb8a 100644
--- a/docs/Ake.md
+++ b/docs/Ake.md
@@ -98,6 +98,12 @@ ake greetings   # finds ../ake and runs it in the project directory
 
 The working directory is automatically set to the project directory (where the ake file lives), so `$` commands always run relative to the project root.
 
+## Global Variables
+
+```ts
+PROJECT_DIR  // absolute path to the project dir
+```
+
 ## Multiple Ake Files
 
 Any file named `ake<suffix>` or `ake<suffix>.ts` is supported.
diff --git a/docs/Global Commands.md b/docs/Global Commands.md
index d87b645..505730a 100644
--- a/docs/Global Commands.md	
+++ b/docs/Global Commands.md	
@@ -76,6 +76,7 @@ $`cat ${files}`                   // cat a.txt b.txt
 ## Global Variables
 
 ```ts
-app      // Command instance for defining CLI metadata and commands
-$        // Shell command tagged template
+app          // Command instance for defining CLI metadata and commands
+$            // Shell command tagged template
+PROJECT_DIR  // ake only: absolute path to the project dir (where the ake file lives)
 ```
diff --git a/src/Command.ts b/src/Command.ts
index 8865b19..1117c5c 100644
--- a/src/Command.ts
+++ b/src/Command.ts
@@ -132,6 +132,7 @@ export class Command {
     }
     const projectDir = getProjectDir(scriptPath)
     process.chdir(projectDir)
+    ;(globalThis as any).PROJECT_DIR = projectDir
   }
 
   async parse(argv: string[]): Promise<void> {
diff --git a/src/globals.d.ts b/src/globals.d.ts
index 0c5e4f6..2f2a719 100644
--- a/src/globals.d.ts
+++ b/src/globals.d.ts
@@ -4,4 +4,5 @@ import type { $ as Shell } from './spawn'
 declare global {
   var app: Command
   var $: typeof Shell
+  var PROJECT_DIR: string
 }