diff --git a/src/posix/cocoa/i_main.mm b/src/posix/cocoa/i_main.mm
index 0a4d16df99..665f2203a6 100644
--- a/src/posix/cocoa/i_main.mm
+++ b/src/posix/cocoa/i_main.mm
@@ -369,8 +369,17 @@ extern bool AppActive;
 		}
 	}
 
-	s_argv.Push("-file");
-	s_argv.Push([filename UTF8String]);
+	bool iwad = false;
+
+	if (const char* const extPos = strrchr(charFileName, '.'))
+	{
+		iwad = 0 == stricmp(extPos, ".iwad")
+			|| 0 == stricmp(extPos, ".ipk3")
+			|| 0 == stricmp(extPos, ".ipk7");
+	}
+
+	s_argv.Push(iwad ? "-iwad" : "-file");
+	s_argv.Push(charFileName);
 
 	return TRUE;
 }
diff --git a/src/posix/osx/zdoom-info.plist b/src/posix/osx/zdoom-info.plist
index a1510254ce..da2263f05e 100644
--- a/src/posix/osx/zdoom-info.plist
+++ b/src/posix/osx/zdoom-info.plist
@@ -38,6 +38,9 @@
 				<string>zip</string>
 				<string>pk7</string>
 				<string>7z</string>
+				<string>iwad</string>
+				<string>ipk3</string>
+				<string>ipk7</string>
 			</array>
 		</dict>
 	</array>