diff --git a/nac3artiq/src/lib.rs b/nac3artiq/src/lib.rs
index ca2f2f15..870713ba 100644
--- a/nac3artiq/src/lib.rs
+++ b/nac3artiq/src/lib.rs
@@ -636,7 +636,8 @@ impl Nac3 {
                     TopLevelDef::Function { codegen_callback, .. } => {
                         *codegen_callback = Some(rpc_codegen_callback(*is_async));
                     }
-                    TopLevelDef::Class { methods, .. } => {
+                    TopLevelDef::Class { methods, .. } | TopLevelDef::Module { methods, .. } => {
+                        // TODO: Update this to handle functions as well
                         let (class_def, method_name) = class_data.as_ref().unwrap();
                         for (name, _, id) in &*methods {
                             if name != method_name {
diff --git a/nac3core/src/codegen/expr.rs b/nac3core/src/codegen/expr.rs
index 0118ca43..0dbf65ee 100644
--- a/nac3core/src/codegen/expr.rs
+++ b/nac3core/src/codegen/expr.rs
@@ -980,6 +980,7 @@ pub fn gen_call<'ctx, G: CodeGenerator>(
                 return Ok(Some(generator.gen_constructor(ctx, fun.0, &def, params)?))
             }
             TopLevelDef::Variable { .. } => unreachable!(),
+            TopLevelDef::Module { .. } => unreachable!(), // TODO: Throw error here
         }
     }
     .or_else(|_: String| {
diff --git a/nac3core/src/toplevel/composer.rs b/nac3core/src/toplevel/composer.rs
index 6040ced1..499fed79 100644
--- a/nac3core/src/toplevel/composer.rs
+++ b/nac3core/src/toplevel/composer.rs
@@ -101,7 +101,9 @@ impl TopLevelComposer {
         let builtin_name_list = definition_ast_list
             .iter()
             .map(|def_ast| match *def_ast.0.read() {
-                TopLevelDef::Class { name, .. } => name.to_string(),
+                TopLevelDef::Class { name, .. } | TopLevelDef::Module { name, .. } => {
+                    name.to_string()
+                }
                 TopLevelDef::Function { simple_name, .. }
                 | TopLevelDef::Variable { simple_name, .. } => simple_name.to_string(),
             })
diff --git a/nac3core/src/toplevel/helper.rs b/nac3core/src/toplevel/helper.rs
index 71c1859b..81eb47b6 100644
--- a/nac3core/src/toplevel/helper.rs
+++ b/nac3core/src/toplevel/helper.rs
@@ -359,6 +359,23 @@ pub fn make_exception_fields(int32: Type, int64: Type, str: Type) -> Vec<(StrRef
 impl TopLevelDef {
     pub fn to_string(&self, unifier: &mut Unifier) -> String {
         match self {
+            TopLevelDef::Module { name, fields, methods, .. } => {
+                let fields_str = fields
+                    .iter()
+                    .map(|(n, ty, _)| (n.to_string(), unifier.stringify(*ty)))
+                    .collect_vec();
+
+                let methods_str = methods
+                    .iter()
+                    .map(|(n, ty, id)| (n.to_string(), unifier.stringify(*ty), *id))
+                    .collect_vec();
+                format!(
+                    "Module {{\nname: {:?},\nfields: {:?},\nmethods: {:?}\n}}",
+                    name,
+                    fields_str.iter().map(|(a, _)| a).collect_vec(),
+                    methods_str.iter().map(|(a, b, _)| (a, b)).collect_vec(),
+                )
+            }
             TopLevelDef::Class { name, ancestors, fields, methods, type_vars, .. } => {
                 let fields_str = fields
                     .iter()
diff --git a/nac3core/src/toplevel/mod.rs b/nac3core/src/toplevel/mod.rs
index cba2f5e7..346932ef 100644
--- a/nac3core/src/toplevel/mod.rs
+++ b/nac3core/src/toplevel/mod.rs
@@ -92,6 +92,24 @@ pub struct FunInstance {
 
 #[derive(Debug, Clone)]
 pub enum TopLevelDef {
+    Module {
+        /// Module name
+        name: StrRef,
+        /// Module fields.
+        ///
+        /// Name and type is mutable.
+        fields: Vec<(StrRef, Type, bool)>,
+        /// Module Attributes.
+        ///
+        /// Name, type, value.
+        attributes: Vec<(StrRef, Type, ast::Constant)>,
+        /// Class methods, pointing to the corresponding function definition.
+        methods: Vec<(StrRef, Type, DefinitionId)>,
+        /// Symbol resolver of the module defined the class; [None] if it is built-in type.
+        resolver: Option<Arc<dyn SymbolResolver + Send + Sync>>,
+        /// Definition location.
+        loc: Option<Location>,
+    },
     Class {
         /// Name for error messages and symbols.
         name: StrRef,
diff --git a/nac3core/src/typecheck/type_inferencer/mod.rs b/nac3core/src/typecheck/type_inferencer/mod.rs
index 6068f630..a057e894 100644
--- a/nac3core/src/typecheck/type_inferencer/mod.rs
+++ b/nac3core/src/typecheck/type_inferencer/mod.rs
@@ -2695,7 +2695,7 @@ impl<'a> Inferencer<'a> {
             .read()
             .iter()
             .map(|def| match *def.read() {
-                TopLevelDef::Class { name, .. } => (name, false),
+                TopLevelDef::Class { name, .. } | TopLevelDef::Module { name, .. } => (name, false), // TODO: Check if should be global
                 TopLevelDef::Function { simple_name, .. } => (simple_name, false),
                 TopLevelDef::Variable { simple_name, .. } => (simple_name, true),
             })