diff --git a/changelog/next.md b/changelog/next.md
index 7e4f81b..db46e8e 100644
--- a/changelog/next.md
+++ b/changelog/next.md
@@ -44,6 +44,7 @@ set shell id.
 - Added `QS_CRASHREPORT_URL` environment variable to allow overriding the crash reporter link.
 - Added `AppId` pragma and `QS_APP_ID` environment variable to allow overriding the desktop application ID.
 - Added `DropExpensiveFonts` pragma and `QS_DROP_EXPENSIVE_FONTS` environment variable which avoids loading fonts which may cause lag and excessive memory usage if many variants are used.
+- Added `DefaultEnv` pragma which sets an environment variable if not already set.
 - Unrecognized pragmas are no longer a hard error for future backward compatibility.
 
 ## Bug Fixes
diff --git a/src/launch/launch.cpp b/src/launch/launch.cpp
index dcdefa7..71d9983 100644
--- a/src/launch/launch.cpp
+++ b/src/launch/launch.cpp
@@ -76,6 +76,7 @@ int launch(const LaunchArgs& args, char** argv, QCoreApplication* coreApplicatio
 		bool useSystemStyle = false;
 		QString iconTheme = qEnvironmentVariable("QS_ICON_THEME");
 		QHash<QString, QString> envOverrides;
+		QHash<QString, QString> defaultEnv;
 		QString appId = qEnvironmentVariable("QS_APP_ID");
 		bool dropExpensiveFonts = false;
 		QString dataDir;
@@ -89,25 +90,30 @@ int launch(const LaunchArgs& args, char** argv, QCoreApplication* coreApplicatio
 		if (line.startsWith("//@ pragma ")) {
 			auto pragma = line.sliced(11).trimmed();
 
-			if (pragma == "UseQApplication") pragmas.useQApplication = true;
-			else if (pragma == "NativeTextRendering") pragmas.nativeTextRendering = true;
-			else if (pragma == "IgnoreSystemSettings") pragmas.desktopSettingsAware = false;
-			else if (pragma == "RespectSystemStyle") pragmas.useSystemStyle = true;
-			else if (pragma == "DropExpensiveFonts") pragmas.dropExpensiveFonts = true;
-			else if (pragma.startsWith("IconTheme ")) pragmas.iconTheme = pragma.sliced(10);
-			else if (pragma.startsWith("Env ")) {
-				auto envPragma = pragma.sliced(4);
-				auto splitIdx = envPragma.indexOf('=');
+			auto isEnv = pragma.startsWith("Env ");
+			auto isDefaultEnv = pragma.startsWith("DefaultEnv ");
+
+			if (isEnv || isDefaultEnv) {
+				auto content = pragma.sliced(isDefaultEnv ? 11 : 4);
+				auto splitIdx = content.indexOf('=');
 
 				if (splitIdx == -1) {
 					qCritical() << "Env pragma" << pragma << "not in the form 'VAR = VALUE'";
 					return -1;
 				}
 
-				auto var = envPragma.sliced(0, splitIdx).trimmed();
-				auto val = envPragma.sliced(splitIdx + 1).trimmed();
-				pragmas.envOverrides.insert(var, val);
-			} else if (pragma.startsWith("AppId ")) {
+				auto var = content.sliced(0, splitIdx).trimmed();
+				auto val = content.sliced(splitIdx + 1).trimmed();
+
+				if (isDefaultEnv) pragmas.defaultEnv.insert(var, val);
+				else pragmas.envOverrides.insert(var, val);
+			} else if (pragma == "UseQApplication") pragmas.useQApplication = true;
+			else if (pragma == "NativeTextRendering") pragmas.nativeTextRendering = true;
+			else if (pragma == "IgnoreSystemSettings") pragmas.desktopSettingsAware = false;
+			else if (pragma == "RespectSystemStyle") pragmas.useSystemStyle = true;
+			else if (pragma == "DropExpensiveFonts") pragmas.dropExpensiveFonts = true;
+			else if (pragma.startsWith("IconTheme ")) pragmas.iconTheme = pragma.sliced(10);
+			else if (pragma.startsWith("AppId ")) {
 				pragmas.appId = pragma.sliced(6).trimmed();
 			} else if (pragma.startsWith("ShellId ")) {
 				shellId = pragma.sliced(8).trimmed();
@@ -174,6 +180,10 @@ int launch(const LaunchArgs& args, char** argv, QCoreApplication* coreApplicatio
 		qputenv("QT_QUICK_CONTROLS_STYLE", "Fusion");
 	}
 
+	for (auto [var, val]: pragmas.defaultEnv.asKeyValueRange()) {
+		if (!qEnvironmentVariableIsSet(var.toUtf8())) qputenv(var.toUtf8(), val.toUtf8());
+	}
+
 	for (auto [var, val]: pragmas.envOverrides.asKeyValueRange()) {
 		qputenv(var.toUtf8(), val.toUtf8());
 	}