diff --git a/lib/edlang_codegen_llvm/src/codegen.rs b/lib/edlang_codegen_llvm/src/codegen.rs
index 50e6bdd4e..66efe3024 100644
--- a/lib/edlang_codegen_llvm/src/codegen.rs
+++ b/lib/edlang_codegen_llvm/src/codegen.rs
@@ -221,7 +221,7 @@ fn compile_fn_signature(ctx: &ModuleCompileCtx<'_, '_>, fn_id: DefId) {
     };
 
     let fn_value = ctx.module.add_function(
-        &body.name,
+        &body.get_mangled_name(),
         fn_type,
         Some(if body.is_extern {
             inkwell::module::Linkage::AvailableExternally
@@ -256,7 +256,7 @@ fn compile_fn_signature(ctx: &ModuleCompileCtx<'_, '_>, fn_id: DefId) {
     let subprogram = ctx.di_builder.create_function(
         ctx.di_namespace,
         &body.name,
-        Some(&body.name),
+        Some(&body.get_mangled_name()),
         ctx.di_unit.get_file(),
         line as u32 + 1,
         di_type,
@@ -273,7 +273,7 @@ fn compile_fn(ctx: &ModuleCompileCtx, fn_id: DefId) -> Result<(), BuilderError>
     let body = ctx.ctx.program.functions.get(&fn_id).unwrap();
     trace!("compiling fn body: {}", body.name);
 
-    let fn_value = ctx.module.get_function(&body.name).unwrap();
+    let fn_value = ctx.module.get_function(&body.get_mangled_name()).unwrap();
     let di_program = fn_value.get_subprogram().unwrap();
 
     let mut debug_loc = ctx.set_debug_loc(di_program.as_debug_info_scope(), body.fn_span);
@@ -528,7 +528,10 @@ fn compile_fn(ctx: &ModuleCompileCtx, fn_id: DefId) -> Result<(), BuilderError>
                 target,
             } => {
                 let target_fn_body = ctx.ctx.program.functions.get(func).unwrap();
-                let fn_value = ctx.module.get_function(&target_fn_body.name).unwrap();
+                let fn_value = ctx
+                    .module
+                    .get_function(&target_fn_body.get_mangled_name())
+                    .unwrap();
                 let args: Vec<_> = args
                     .iter()
                     .map(|x| compile_rvalue(ctx, fn_id, &locals, x).unwrap().0.into())
diff --git a/lib/edlang_driver/src/lib.rs b/lib/edlang_driver/src/lib.rs
index f515fbca9..c04fe95ad 100644
--- a/lib/edlang_driver/src/lib.rs
+++ b/lib/edlang_driver/src/lib.rs
@@ -55,10 +55,10 @@ pub fn main() -> Result<(), Box<dyn Error>> {
     let path = args.input.display().to_string();
     let source = std::fs::read_to_string(&args.input)?;
 
-    let module = edlang_parser::parse_ast(&source);
+    let modules = edlang_parser::parse_ast(&source);
 
-    let module = match module {
-        Ok(module) => module,
+    let modules = match modules {
+        Ok(modules) => modules,
         Err(error) => {
             let report = edlang_parser::error_to_report(&path, &error)?;
             edlang_parser::print_report(&path, &source, report)?;
@@ -121,11 +121,11 @@ pub fn main() -> Result<(), Box<dyn Error>> {
     tracing::debug!("Debug Info: {:#?}", session.debug_info);
 
     if args.ast {
-        println!("{:#?}", module);
+        println!("{:#?}", modules);
         return Ok(());
     }
 
-    let program_ir = match lower_modules(&[module.clone()]) {
+    let program_ir = match lower_modules(&modules) {
         Ok(ir) => ir,
         Err(error) => {
             let report = edlang_check::lowering_error_to_report(error, &session);
diff --git a/lib/edlang_driver/tests/common.rs b/lib/edlang_driver/tests/common.rs
index 913df1230..90df33724 100644
--- a/lib/edlang_driver/tests/common.rs
+++ b/lib/edlang_driver/tests/common.rs
@@ -34,7 +34,7 @@ pub fn compile_program(
     name: &str,
     library: bool,
 ) -> Result<CompileResult, Box<dyn std::error::Error>> {
-    let module = edlang_parser::parse_ast(source).unwrap();
+    let modules = edlang_parser::parse_ast(source).unwrap();
 
     let test_dir = tempfile::tempdir()?;
     let test_dir_path = test_dir.path();
@@ -63,7 +63,7 @@ pub fn compile_program(
         output_asm: false,
     };
 
-    let program_ir = lower_modules(&[module])?;
+    let program_ir = lower_modules(&modules)?;
 
     let object_path = edlang_codegen_llvm::compile(&session, &program_ir)?;
 
diff --git a/lib/edlang_ir/src/lib.rs b/lib/edlang_ir/src/lib.rs
index eeb8f1dd6..89de662c9 100644
--- a/lib/edlang_ir/src/lib.rs
+++ b/lib/edlang_ir/src/lib.rs
@@ -89,6 +89,17 @@ impl Body {
     pub fn get_return_local(&self) -> Local {
         self.locals[0].clone()
     }
+
+    pub fn get_mangled_name(&self) -> String {
+        if self.name == "main" {
+            "main".to_string()
+        } else {
+            format!(
+                "{}@{}@{}",
+                self.name, self.def_id.program_id, self.def_id.id
+            )
+        }
+    }
 }
 
 #[derive(Debug, Clone)]
diff --git a/lib/edlang_lowering/src/lib.rs b/lib/edlang_lowering/src/lib.rs
index a9487dc92..89c24131b 100644
--- a/lib/edlang_lowering/src/lib.rs
+++ b/lib/edlang_lowering/src/lib.rs
@@ -58,11 +58,10 @@ fn lower_module(
         }
     }
 
-    let body = ctx.body.modules.get(&id).unwrap();
-
     // fill fn sigs
     for content in &module.contents {
         if let ModuleStatement::Function(fn_def) = content {
+            let body = ctx.body.modules.get(&id).unwrap();
             let fn_id = *body.symbols.functions.get(&fn_def.name.name).unwrap();
 
             let mut args = Vec::new();
@@ -92,7 +91,11 @@ fn lower_module(
                 ctx = lower_function(ctx, fn_def, id)?;
             }
             // ModuleStatement::Type(_) => todo!(),
-            ModuleStatement::Module(_mod_def) => {}
+            ModuleStatement::Module(mod_def) => {
+                let body = ctx.body.modules.get(&id).unwrap();
+                let id = *body.symbols.modules.get(&mod_def.name.name).unwrap();
+                ctx = lower_module(ctx, mod_def, id)?;
+            }
             _ => {}
         }
     }
diff --git a/lib/edlang_parser/src/grammar.lalrpop b/lib/edlang_parser/src/grammar.lalrpop
index 95f0de99a..adf58540d 100644
--- a/lib/edlang_parser/src/grammar.lalrpop
+++ b/lib/edlang_parser/src/grammar.lalrpop
@@ -466,6 +466,10 @@ pub(crate) Import: ast::Import = {
     }
 }
 
+pub Modules: Vec<ast::Module> = {
+  <Module+> => <>
+}
+
 pub Module: ast::Module = {
     <lo:@L> "mod" <name:Ident> "{" <imports:List<Import>?> <contents:List<ModuleStatement>> "}" <hi:@R> => ast::Module {
         name,
diff --git a/lib/edlang_parser/src/lib.rs b/lib/edlang_parser/src/lib.rs
index f44aa5935..382a33a9a 100644
--- a/lib/edlang_parser/src/lib.rs
+++ b/lib/edlang_parser/src/lib.rs
@@ -22,9 +22,9 @@ pub mod grammar {
 
 pub fn parse_ast(
     source: &str,
-) -> Result<edlang_ast::Module, ParseError<usize, Token, LexicalError>> {
+) -> Result<Vec<edlang_ast::Module>, ParseError<usize, Token, LexicalError>> {
     let lexer = Lexer::new(source);
-    let parser = grammar::ModuleParser::new();
+    let parser = grammar::ModulesParser::new();
     parser.parse(lexer)
 }