diff --git a/Sources/XcodeGenKit/SourceGenerator.swift b/Sources/XcodeGenKit/SourceGenerator.swift
index 59b28588..10313f47 100644
--- a/Sources/XcodeGenKit/SourceGenerator.swift
+++ b/Sources/XcodeGenKit/SourceGenerator.swift
@@ -764,7 +764,7 @@ class SourceGenerator {
             sourceReference = group
         case .syncedFolder:
 
-            let relativePath = (try? path.relativePath(from: project.basePath)) ?? path
+            let relativePath = (try? path.relativePath(from: basePath)) ?? path
             let resolvedExplicitFolders = resolveExplicitFolders(targetSource: targetSource)
 
             let syncedRootGroup: PBXFileSystemSynchronizedRootGroup
diff --git a/Tests/XcodeGenKitTests/SourceGeneratorTests.swift b/Tests/XcodeGenKitTests/SourceGeneratorTests.swift
index b8450c5f..f24ad71e 100644
--- a/Tests/XcodeGenKitTests/SourceGeneratorTests.swift
+++ b/Tests/XcodeGenKitTests/SourceGeneratorTests.swift
@@ -102,6 +102,27 @@ class SourceGeneratorTests: XCTestCase {
                 try expect([syncedFolder]) == pbxProj.nativeTargets.first?.fileSystemSynchronizedGroups
             }
 
+            $0.it("generates synced folder with different projectDirectory") {
+                let directories = """
+                SubDir:
+                  Sources:
+                    - a.swift
+                """
+                try createDirectories(directories)
+
+                let target = Target(name: "Test", type: .application, platform: .iOS, sources: [.init(path: "Sources", type: .syncedFolder)])
+                let project = Project(basePath: directoryPath + "SubDir", name: "Test", targets: [target])
+
+                let generator = PBXProjGenerator(project: project, projectDirectory: directoryPath)
+                let pbxProj = try generator.generate()
+
+                let syncedFolders = try pbxProj.getMainGroup().children.compactMap { $0 as? PBXFileSystemSynchronizedRootGroup }
+                let syncedFolder = try unwrap(syncedFolders.first)
+
+                try expect(syncedFolder.path) == "SubDir/Sources"
+                try expect([syncedFolder]) == pbxProj.nativeTargets.first?.fileSystemSynchronizedGroups
+            }
+
             $0.it("generates synced folder with explicitFolders") {
                 let directories = """
                 Sources: