diff --git a/swift/apple/Firezone.xcodeproj/project.pbxproj b/swift/apple/Firezone.xcodeproj/project.pbxproj
index d9e14e214..bca247989 100644
--- a/swift/apple/Firezone.xcodeproj/project.pbxproj
+++ b/swift/apple/Firezone.xcodeproj/project.pbxproj
@@ -727,6 +727,7 @@
 					"DEBUG=1",
 					"$(inherited)",
 				);
+				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
 				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
 				GCC_WARN_UNDECLARED_SELECTOR = YES;
@@ -741,6 +742,7 @@
 				SUPPORTED_PLATFORMS = "macosx iphoneos";
 				SWIFT_ACTIVE_COMPILATION_CONDITIONS = DEBUG;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
+				SWIFT_TREAT_WARNINGS_AS_ERRORS = YES;
 			};
 			name = Debug;
 		};
@@ -786,6 +788,7 @@
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu11;
 				GCC_NO_COMMON_BLOCKS = YES;
+				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
 				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
 				GCC_WARN_UNDECLARED_SELECTOR = YES;
@@ -799,6 +802,7 @@
 				SUPPORTED_PLATFORMS = "macosx iphoneos";
 				SWIFT_COMPILATION_MODE = wholemodule;
 				SWIFT_OPTIMIZATION_LEVEL = "-O";
+				SWIFT_TREAT_WARNINGS_AS_ERRORS = YES;
 			};
 			name = Release;
 		};