diff --git a/libs/ast/include/pslang/ast/statement.hpp b/libs/ast/include/pslang/ast/statement.hpp
index a5c3649..f968469 100644
--- a/libs/ast/include/pslang/ast/statement.hpp
+++ b/libs/ast/include/pslang/ast/statement.hpp
@@ -28,6 +28,7 @@ namespace pslang::ast
 
 	struct return_statement
 	{
+		// can be null, which means "return unit"
 		expression_ptr value;
 	};
 
diff --git a/libs/ast/source/print.cpp b/libs/ast/source/print.cpp
index 3e50c46..187dfac 100644
--- a/libs/ast/source/print.cpp
+++ b/libs/ast/source/print.cpp
@@ -267,7 +267,8 @@ namespace pslang::ast
 		put_indent(out, options);
 		out << "return";
 		newline(out);
-		print(out, node.value, child(options));
+		if (node.value)
+			print(out, node.value, child(options));
 	}
 
 	void print(std::ostream & out, statement_ptr const & node, print_options const & options)
diff --git a/libs/interpreter/source/interpreter.cpp b/libs/interpreter/source/interpreter.cpp
index 19b7f13..18a27ad 100644
--- a/libs/interpreter/source/interpreter.cpp
+++ b/libs/interpreter/source/interpreter.cpp
@@ -180,7 +180,7 @@ namespace pslang::interpreter
 
 		void execute_impl(context & context, ast::return_statement const & return_statement)
 		{
-			auto value = eval(context, return_statement.value);
+			auto value = return_statement.value ? eval(context, return_statement.value) : unit_value{};
 			for (auto it = context.scope_stack.rbegin(); it != context.scope_stack.rend(); ++it)
 			{
 				if (it->is_function_scope)
diff --git a/libs/parser/rules/pslang.y b/libs/parser/rules/pslang.y
index f1514d5..ec3ae24 100644
--- a/libs/parser/rules/pslang.y
+++ b/libs/parser/rules/pslang.y
@@ -188,6 +188,7 @@ statement
 | while expression colon { $$ = ast::while_block{std::make_unique<ast::expression>($2), {}}; }
 | func name lparen function_definition_argument_list rparen function_return_type colon { $$ = ast::function_definition{$2, $4, $6, {}}; }
 | return expression { $$ = ast::return_statement{std::make_unique<ast::expression>($2)}; }
+| return { $$ = ast::return_statement{nullptr}; }
 ;
 
 function_definition_argument_list