diff --git a/src/analysis.ts b/src/analysis.ts
index 2e4f0aab7..b0c366b13 100644
--- a/src/analysis.ts
+++ b/src/analysis.ts
@@ -37,6 +37,7 @@ export class Analyser {
         }
 
         case SyntaxKind.SourceFile:
+        case SyntaxKind.ModuleDeclaration:
         {
           for (const element of node.elements) {
             visit(element, source);
diff --git a/src/checker.ts b/src/checker.ts
index 62cbf81c2..7ffe4ec01 100644
--- a/src/checker.ts
+++ b/src/checker.ts
@@ -1103,6 +1103,7 @@ export class Checker {
     switch (node.kind) {
 
       case SyntaxKind.SourceFile:
+      case SyntaxKind.ModuleDeclaration:
       {
         for (const element of node.elements) {
           this.infer(element);
@@ -1588,6 +1589,7 @@ export class Checker {
     switch (node.kind) {
 
       case SyntaxKind.SourceFile:
+      case SyntaxKind.ModuleDeclaration:
       {
         const env = node.typeEnv = new TypeEnv(parentEnv);
         for (const element of node.elements) {
diff --git a/src/cst.ts b/src/cst.ts
index ac855f080..54af309df 100644
--- a/src/cst.ts
+++ b/src/cst.ts
@@ -182,14 +182,14 @@ export const enum SyntaxKind {
   Initializer,
   TypeAssert,
   Param,
-  Module,
+  ModuleDeclaration,
   SourceFile,
 
 }
 
 export type Syntax
   = SourceFile
-  | Module
+  | ModuleDeclaration
   | Token
   | Param
   | Body
@@ -220,7 +220,8 @@ function isNodeWithScope(node: Syntax): node is NodeWithScope {
 export const enum Symkind {
   Var = 1,
   Type = 2,
-  Any = Var | Type
+  Module = 4,
+  Any = Var | Type | Module
 }
 
 export class Scope {
@@ -267,6 +268,14 @@ export class Scope {
         }
         break;
       }
+      case SyntaxKind.ModuleDeclaration:
+      {
+        this.add(node.name.text, node, Symkind.Module);
+        for (const element of node.elements) {
+          this.scan(element);
+        }
+        break;
+      }
       case SyntaxKind.ExpressionStatement:
       case SyntaxKind.ReturnStatement:
       case SyntaxKind.IfStatement:
@@ -2194,15 +2203,18 @@ export class Initializer extends SyntaxBase {
 
 }
 
-export class Module extends SyntaxBase {
+export class ModuleDeclaration extends SyntaxBase {
 
-  public readonly kind = SyntaxKind.Module;
+  public readonly kind = SyntaxKind.ModuleDeclaration;
+
+  public typeEnv?: TypeEnv;
 
   public constructor(
     public pubKeyword: PubKeyword | null,
     public modKeyword: ModKeyword,
-    public name: Identifier,
-    public body: Body,
+    public name: IdentifierAlt,
+    public blockStart: BlockStart,
+    public elements: SourceFileElement[],
   ) {
     super();
   }
@@ -2215,7 +2227,10 @@ export class Module extends SyntaxBase {
   }
 
   public getLastToken(): Token {
-    return this.body.getLastToken();
+    if (this.elements.length > 0) {
+      return this.elements[this.elements.length-1].getLastToken();
+    }
+    return this.blockStart;
   }
 
 }
@@ -2223,7 +2238,7 @@ export class Module extends SyntaxBase {
 export type SourceFileElement
   = Statement
   | Declaration
-  | Module
+  | ModuleDeclaration
 
 export class SourceFile extends SyntaxBase {
 
diff --git a/src/parser.ts b/src/parser.ts
index f0468b6c1..cc5199f7e 100644
--- a/src/parser.ts
+++ b/src/parser.ts
@@ -59,6 +59,7 @@ import {
   LiteralPattern,
   DisjunctivePattern,
   TupleTypeExpression,
+  ModuleDeclaration,
 } from "./cst"
 import { Stream } from "./util";
 
@@ -954,11 +955,38 @@ export class Parser {
     return new ImportDeclaration(importKeyword, importSource);
   }
 
+  public parseModuleDeclaration(): ModuleDeclaration {
+    let pubKeyword = null;
+    let t0 = this.getToken();
+    if (t0.kind === SyntaxKind.PubKeyword) {
+      pubKeyword = t0;
+      t0 = this.getToken();
+    }
+    if (t0.kind !== SyntaxKind.ModKeyword) {
+      this.raiseParseError(t0, [ SyntaxKind.ModKeyword ]);
+    }
+    const name = this.expectToken(SyntaxKind.IdentifierAlt);
+    const blockStart = this.expectToken(SyntaxKind.BlockStart);
+    const elements = [];
+    for (;;) {
+      const t1 = this.peekToken();
+      if (t1.kind === SyntaxKind.BlockEnd) {
+        this.getToken();
+        break;
+      }
+      elements.push(this.parseSourceFileElement());
+    }
+    this.expectToken(SyntaxKind.LineFoldEnd);
+    return new ModuleDeclaration(pubKeyword, t0, name, blockStart, elements);
+  }
+
   public parseSourceFileElement(): SourceFileElement {
     const t0 = this.peekTokenAfterModifiers();
     switch (t0.kind) {
       case SyntaxKind.LetKeyword:
         return this.parseLetDeclaration();
+      case SyntaxKind.ModKeyword:
+        return this.parseModuleDeclaration();
       case SyntaxKind.ImportKeyword:
         return this.parseImportDeclaration();
       case SyntaxKind.StructKeyword:
diff --git a/src/scanner.ts b/src/scanner.ts
index 93a147905..f4babeed4 100644
--- a/src/scanner.ts
+++ b/src/scanner.ts
@@ -41,6 +41,7 @@ import {
   RArrowAlt,
   VBar,
   ForeignKeyword,
+  ModKeyword,
 } from "./cst"
 import { Diagnostics, UnexpectedCharDiagnostic } from "./diagnostics"
 import { Stream, BufferedStream, assert } from "./util";
@@ -368,6 +369,7 @@ export class Scanner extends BufferedStream<Token> {
             case 'enum': return new EnumKeyword(startPos);
             case 'match': return new MatchKeyword(startPos);
             case 'foreign': return new ForeignKeyword(startPos);
+            case 'mod': return new ModKeyword(startPos);
             default:
               if (isUpper(text[0])) {
                 return new IdentifierAlt(text, startPos);