diff --git a/lib/pbxProject.js b/lib/pbxProject.js
index 41bc398..25bd8f3 100644
--- a/lib/pbxProject.js
+++ b/lib/pbxProject.js
@@ -1621,6 +1621,12 @@ function pbxShellScriptBuildPhaseObj (obj, options, phaseName) {
         obj.runOnlyForDeploymentPostprocessing = 1;
     }
 
+    // By default, alwaysOutOfDate is not set and treated as false.
+    // Any truthy value, it will be set to 1, including any non-empty strings.
+    if (options.alwaysOutOfDate) {
+        obj.alwaysOutOfDate = 1;
+    }
+
     return obj;
 }
 
diff --git a/test/addBuildPhase.js b/test/addBuildPhase.js
index d3249b9..5d1ace2 100644
--- a/test/addBuildPhase.js
+++ b/test/addBuildPhase.js
@@ -197,4 +197,26 @@ describe('addBuildPhase', () => {
         const buildPhase = proj.addBuildPhase([], 'PBXShellScriptBuildPhase', 'Run a script', proj.getFirstTarget().uuid, options).buildPhase;
         assert.equal(buildPhase.runOnlyForDeploymentPostprocessing, 1);
     });
+
+    it('should add the PBXBuildPhase with alwaysOutOfDate property', () => {
+        const options = {
+            shellPath: '/bin/sh',
+            shellScript: 'test',
+            alwaysOutOfDate: true
+        };
+
+        const buildPhase = proj.addBuildPhase([], 'PBXShellScriptBuildPhase', 'Run a script', proj.getFirstTarget().uuid, options).buildPhase;
+        assert.equal(buildPhase.shellPath, '/bin/sh');
+        assert.equal(buildPhase.shellScript, '"test"');
+        assert.strictEqual(buildPhase.alwaysOutOfDate, 1);
+    });
+
+    it('should add the PBXBuildPhase without alwaysOutOfDate property', () => {
+        const options = { shellPath: '/bin/sh', shellScript: 'test' };
+
+        const buildPhase = proj.addBuildPhase([], 'PBXShellScriptBuildPhase', 'Run a script', proj.getFirstTarget().uuid, options).buildPhase;
+        assert.equal(buildPhase.shellPath, '/bin/sh');
+        assert.equal(buildPhase.shellScript, '"test"');
+        assert.strictEqual(buildPhase.alwaysOutOfDate, undefined);
+    });
 });