diff --git a/README.md b/README.md
index 85411e642..4b0703df9 100644
--- a/README.md
+++ b/README.md
@@ -85,7 +85,7 @@ Examples
 
 ### Using .proto files
 
-It's possible to load existing .proto files using the full library, which parses and compiles the definitions to ready to use reflection-based runtime message classes:
+It's possible to load existing .proto files using the full library, which parses and compiles the definitions to ready to use (reflection-based) message classes:
 
 ```protobuf
 // awesome.proto
@@ -441,7 +441,7 @@ $> pbjs -t static-module -w commonjs -o compiled.js file1.proto file2.proto
 $> pbts -o compiled.d.ts compiled.js
 ```
 
-Additionally, TypeScript definitions of static modules are compatible with reflection, as long as the following conditions are met:
+Additionally, TypeScript definitions of static modules are compatible with their reflection-based counterparts (i.e. as exported by JSON modules), as long as the following conditions are met:
 
 1. Instead of using `new SomeMessage(...)`, always use `SomeMessage.create(...)` because reflection objects do not provide a constructor.
 2. Types, services and enums must start with an uppercase letter to become available as properties of the reflected types as well (i.e. to be able to use `MyMessage.MyEnum` instead of `root.lookup("MyMessage.MyEnum")`).
diff --git a/cli/pbjs.js b/cli/pbjs.js
index 56b337685..9e1c01ca0 100644
--- a/cli/pbjs.js
+++ b/cli/pbjs.js
@@ -31,7 +31,7 @@ exports.main = function(args, callback) {
             lint   : "l"
         },
         string: [ "target", "out", "path", "wrap", "root", "lint" ],
-        boolean: [ "keep-case", "create", "encode", "decode", "verify", "convert", "delimited", "beautify", "comments" ],
+        boolean: [ "keep-case", "create", "encode", "decode", "verify", "convert", "delimited", "beautify", "comments", "es6" ],
         default: {
             target    : "json",
             create    : true,
@@ -42,13 +42,14 @@ exports.main = function(args, callback) {
             delimited : true,
             beautify  : true,
             comments  : true,
+            es6       : null,
             lint      : lintDefault
         }
     });
 
     var target = targets[argv.target],
         files  = argv._,
-        paths  = typeof argv.path === 'string' ? [ argv.path ] : argv.path || [];
+        paths  = typeof argv.path === "string" ? [ argv.path ] : argv.path || [];
 
     if (!files.length) {
         var descs = Object.keys(targets).filter(function(key) { return !targets[key].private; }).map(function(key) {
@@ -77,7 +78,7 @@ exports.main = function(args, callback) {
                 "                  default   Default wrapper supporting both CommonJS and AMD",
                 "                  commonjs  CommonJS wrapper",
                 "                  amd       AMD wrapper",
-                "                  es6       ES6 wrapper",
+                "                  es6       ES6 wrapper (implies --es6)",
                 "",
                 "  -r, --root      Specifies an alternative protobuf.roots name.",
                 "",
@@ -85,6 +86,8 @@ exports.main = function(args, callback) {
                 "",
                 "                  " + lintDefault,
                 "",
+                "  --es6           Enables ES6 syntax (const/let instead of var)",
+                "",
                 chalk.bold.gray("  Proto sources only:"),
                 "",
                 "  --keep-case     Keeps field casing instead of converting to camel case.",
@@ -134,6 +137,10 @@ exports.main = function(args, callback) {
         return filepath;
     };
 
+    // Use es6 syntax if not explicitly specified on the command line and the es6 wrapper is used
+    if (argv.wrap === "es6" && argv.es6 === null)
+        argv.es6 = true;
+
     var parseOptions = {
         "keepCase": argv["keep-case"] || false
     };
diff --git a/cli/targets/json-module.js b/cli/targets/json-module.js
index e707b5068..3b1c93779 100644
--- a/cli/targets/json-module.js
+++ b/cli/targets/json-module.js
@@ -9,7 +9,7 @@ function json_module(root, options, callback) {
     try {       
         var rootProp = util.safeProp(options.root || "default");
         var output = [
-            "var $root = ($protobuf.roots" + rootProp + " || ($protobuf.roots" + rootProp + " = new $protobuf.Root()))\n"
+            (options.es6 ? "const" : "var") + " $root = ($protobuf.roots" + rootProp + " || ($protobuf.roots" + rootProp + " = new $protobuf.Root()))\n"
         ];
         if (root.options) {
             var optionsJson = util.jsonSafeProp(JSON.stringify(root.options, null, 2));
diff --git a/cli/targets/static.js b/cli/targets/static.js
index 5230ab397..3488d7d80 100644
--- a/cli/targets/static.js
+++ b/cli/targets/static.js
@@ -25,13 +25,11 @@ function static_target(root, options, callback) {
     try {
         if (config.comments)
             push("// Common aliases");
-        push("var $Reader = $protobuf.Reader,");
-        push("    $Writer = $protobuf.Writer,");
-        push("    $util   = $protobuf.util;");
+        push((config.es6 ? "const" : "var") + " $Reader = $protobuf.Reader, $Writer = $protobuf.Writer, $util = $protobuf.util;");
         push("");
         if (config.comments)
             push("// Lazily resolved type references");
-        push("var $lazyTypes = [];");
+        push((config.es6 ? "const" : "var") + " $lazyTypes = [];");
         push("");
         if (config.comments) {
             if (root.comment)
@@ -40,7 +38,7 @@ function static_target(root, options, callback) {
                 push("// Exported root namespace");
         }
         var rootProp = cliUtil.safeProp(config.root || "default");
-        push("var $root = $protobuf.roots" + rootProp + " || ($protobuf.roots" + rootProp + " = {});");
+        push((config.es6 ? "const" : "var") + " $root = $protobuf.roots" + rootProp + " || ($protobuf.roots" + rootProp + " = {});");
         buildNamespace(null, root);
         push("");
         if (config.comments)
@@ -113,7 +111,7 @@ function buildNamespace(ref, ns) {
             "@exports " + ns.fullName.substring(1),
             "@namespace"
         ]);
-        push("var " + name(ns.name) + " = {};");
+        push((config.es6 ? "const" : "var") + " " + name(ns.name) + " = {};");
     }
 
     ns.nestedArray.forEach(function(nested) {
@@ -172,6 +170,11 @@ function beautifyCode(code) {
                     "type": "Identifier",
                     "name": shortVars[node.name]
                 };
+            // replace var with let if es6
+            if (config.es6 && node.type === "VariableDeclaration" && node.kind === "var") {
+                node.kind = "let";
+                return undefined;
+            }
             // remove braces around block statements with a single child
             if (node.type === "BlockStatement" && reduceableBlockStatements[parent.type] && node.body.length === 1)
                 return node.body[0];
@@ -281,7 +284,7 @@ function buildType(ref, type) {
         ++indent;
         push("if (properties)");
             ++indent;
-            push("for (var keys = Object.keys(properties), i = 0; i < keys.length; ++i)");
+            push("for (" + (config.es6 ? "let" : "var") + " keys = Object.keys(properties), i = 0; i < keys.length; ++i)");
                 ++indent;
                 push("this[keys[i]] = properties[keys[i]];");
                 --indent;
@@ -327,14 +330,14 @@ function buildType(ref, type) {
     });
 
     // virtual oneof fields
-    var firstOneOf = true;;
+    var firstOneOf = true;
     type.oneofsArray.forEach(function(oneof) {
         if (firstOneOf) {
             firstOneOf = false;
             push("");
             if (config.comments)
                 push("// OneOf field names bound to virtual getters and setters");
-            push("var $oneOfFields;");
+            push((config.es6 ? "let" : "var") + " $oneOfFields;");
         }
         oneof.resolve();
         push("");
@@ -364,7 +367,7 @@ function buildType(ref, type) {
         push("");
         if (config.comments)
             push("// Lazily resolved type references");
-        push("var $types = {");
+        push((config.es6 ? "const" : "var") + " $types = {");
         ++indent;
             types.forEach(function(line, i) {
                 push(line + (i === types.length - 1 ? "" : ","));
@@ -609,8 +612,7 @@ function buildEnum(ref, enm) {
     pushComment(comment);
     push(name(ref) + "." + name(enm.name) + " = (function() {");
     ++indent;
-        push("var valuesById = {},");
-        push("    values = Object.create(valuesById);");
+        push((config.es6 ? "const" : "var") + " valuesById = {}, values = Object.create(valuesById);");
         Object.keys(enm.values).forEach(function(key) {
             var val = enm.values[key];
             push("values[valuesById[" + val + "] = " + JSON.stringify(key) + "] = " + val + ";");
diff --git a/tests/data/comments.js b/tests/data/comments.js
index 64e9175ed..361e0b86c 100644
--- a/tests/data/comments.js
+++ b/tests/data/comments.js
@@ -4,9 +4,7 @@
 var $protobuf = require("../../minimal");
 
 // Common aliases
-var $Reader = $protobuf.Reader,
-    $Writer = $protobuf.Writer,
-    $util   = $protobuf.util;
+var $Reader = $protobuf.Reader, $Writer = $protobuf.Writer, $util = $protobuf.util;
 
 // Lazily resolved type references
 var $lazyTypes = [];
@@ -362,8 +360,7 @@ $root.Test2 = (function() {
  * @property {number} THREE=3 Value with a comment.
  */
 $root.Test3 = (function() {
-    var valuesById = {},
-        values = Object.create(valuesById);
+    var valuesById = {}, values = Object.create(valuesById);
     values[valuesById[1] = "ONE"] = 1;
     values[valuesById[2] = "TWO"] = 2;
     values[valuesById[3] = "THREE"] = 3;
diff --git a/tests/data/convert.js b/tests/data/convert.js
index e8a777871..1d5340a25 100644
--- a/tests/data/convert.js
+++ b/tests/data/convert.js
@@ -4,9 +4,7 @@
 var $protobuf = require("../../minimal");
 
 // Common aliases
-var $Reader = $protobuf.Reader,
-    $Writer = $protobuf.Writer,
-    $util   = $protobuf.util;
+var $Reader = $protobuf.Reader, $Writer = $protobuf.Writer, $util = $protobuf.util;
 
 // Lazily resolved type references
 var $lazyTypes = [];
@@ -505,8 +503,7 @@ $root.Message = (function() {
      * @property {number} TWO=2 TWO value
      */
     Message.SomeEnum = (function() {
-        var valuesById = {},
-            values = Object.create(valuesById);
+        var valuesById = {}, values = Object.create(valuesById);
         values[valuesById[1] = "ONE"] = 1;
         values[valuesById[2] = "TWO"] = 2;
         return values;
diff --git a/tests/data/mapbox/vector_tile.js b/tests/data/mapbox/vector_tile.js
index 3e8634700..cd5191d1d 100644
--- a/tests/data/mapbox/vector_tile.js
+++ b/tests/data/mapbox/vector_tile.js
@@ -4,9 +4,7 @@
 var $protobuf = require("../../../minimal");
 
 // Common aliases
-var $Reader = $protobuf.Reader,
-    $Writer = $protobuf.Writer,
-    $util   = $protobuf.util;
+var $Reader = $protobuf.Reader, $Writer = $protobuf.Writer, $util = $protobuf.util;
 
 // Lazily resolved type references
 var $lazyTypes = [];
@@ -216,8 +214,7 @@ $root.vector_tile = (function() {
          * @property {number} POLYGON=3 POLYGON value
          */
         Tile.GeomType = (function() {
-            var valuesById = {},
-                values = Object.create(valuesById);
+            var valuesById = {}, values = Object.create(valuesById);
             values[valuesById[0] = "UNKNOWN"] = 0;
             values[valuesById[1] = "POINT"] = 1;
             values[valuesById[2] = "LINESTRING"] = 2;
diff --git a/tests/data/package.js b/tests/data/package.js
index 559e20851..5797fd625 100644
--- a/tests/data/package.js
+++ b/tests/data/package.js
@@ -4,9 +4,7 @@
 var $protobuf = require("../../minimal");
 
 // Common aliases
-var $Reader = $protobuf.Reader,
-    $Writer = $protobuf.Writer,
-    $util   = $protobuf.util;
+var $Reader = $protobuf.Reader, $Writer = $protobuf.Writer, $util = $protobuf.util;
 
 // Lazily resolved type references
 var $lazyTypes = [];
diff --git a/tests/data/rpc.js b/tests/data/rpc.js
index ccb79902f..192fb88c0 100644
--- a/tests/data/rpc.js
+++ b/tests/data/rpc.js
@@ -4,9 +4,7 @@
 var $protobuf = require("../../minimal");
 
 // Common aliases
-var $Reader = $protobuf.Reader,
-    $Writer = $protobuf.Writer,
-    $util   = $protobuf.util;
+var $Reader = $protobuf.Reader, $Writer = $protobuf.Writer, $util = $protobuf.util;
 
 // Lazily resolved type references
 var $lazyTypes = [];
diff --git a/tests/data/test.js b/tests/data/test.js
index 1b3e84f58..5a3376a3e 100644
--- a/tests/data/test.js
+++ b/tests/data/test.js
@@ -4,9 +4,7 @@
 var $protobuf = require("../../minimal");
 
 // Common aliases
-var $Reader = $protobuf.Reader,
-    $Writer = $protobuf.Writer,
-    $util   = $protobuf.util;
+var $Reader = $protobuf.Reader, $Writer = $protobuf.Writer, $util = $protobuf.util;
 
 // Lazily resolved type references
 var $lazyTypes = [];
@@ -177,8 +175,7 @@ $root.jspb = (function() {
          * @property {number} BAR=2 BAR value
          */
         test.OuterEnum = (function() {
-            var valuesById = {},
-                values = Object.create(valuesById);
+            var valuesById = {}, values = Object.create(valuesById);
             values[valuesById[1] = "FOO"] = 1;
             values[valuesById[2] = "BAR"] = 2;
             return values;
@@ -3135,8 +3132,7 @@ $root.jspb = (function() {
              * @property {number} E2=77 E2 value
              */
             DefaultValues.Enum = (function() {
-                var valuesById = {},
-                    values = Object.create(valuesById);
+                var valuesById = {}, values = Object.create(valuesById);
                 values[valuesById[13] = "E1"] = 13;
                 values[valuesById[77] = "E2"] = 77;
                 return values;
@@ -6497,8 +6493,7 @@ $root.jspb = (function() {
          * @property {number} MAP_VALUE_BAZ_NOBINARY=2 MAP_VALUE_BAZ_NOBINARY value
          */
         test.MapValueEnumNoBinary = (function() {
-            var valuesById = {},
-                values = Object.create(valuesById);
+            var valuesById = {}, values = Object.create(valuesById);
             values[valuesById[0] = "MAP_VALUE_FOO_NOBINARY"] = 0;
             values[valuesById[1] = "MAP_VALUE_BAR_NOBINARY"] = 1;
             values[valuesById[2] = "MAP_VALUE_BAZ_NOBINARY"] = 2;
@@ -9177,8 +9172,7 @@ $root.google = (function() {
              * @property {number} TYPE_SINT64=18 TYPE_SINT64 value
              */
             FieldDescriptorProto.Type = (function() {
-                var valuesById = {},
-                    values = Object.create(valuesById);
+                var valuesById = {}, values = Object.create(valuesById);
                 values[valuesById[1] = "TYPE_DOUBLE"] = 1;
                 values[valuesById[2] = "TYPE_FLOAT"] = 2;
                 values[valuesById[3] = "TYPE_INT64"] = 3;
@@ -9210,8 +9204,7 @@ $root.google = (function() {
              * @property {number} LABEL_REPEATED=3 LABEL_REPEATED value
              */
             FieldDescriptorProto.Label = (function() {
-                var valuesById = {},
-                    values = Object.create(valuesById);
+                var valuesById = {}, values = Object.create(valuesById);
                 values[valuesById[1] = "LABEL_OPTIONAL"] = 1;
                 values[valuesById[2] = "LABEL_REQUIRED"] = 2;
                 values[valuesById[3] = "LABEL_REPEATED"] = 3;
@@ -10827,8 +10820,7 @@ $root.google = (function() {
              * @property {number} LITE_RUNTIME=3 LITE_RUNTIME value
              */
             FileOptions.OptimizeMode = (function() {
-                var valuesById = {},
-                    values = Object.create(valuesById);
+                var valuesById = {}, values = Object.create(valuesById);
                 values[valuesById[1] = "SPEED"] = 1;
                 values[valuesById[2] = "CODE_SIZE"] = 2;
                 values[valuesById[3] = "LITE_RUNTIME"] = 3;
@@ -11447,8 +11439,7 @@ $root.google = (function() {
              * @property {number} STRING_PIECE=2 STRING_PIECE value
              */
             FieldOptions.CType = (function() {
-                var valuesById = {},
-                    values = Object.create(valuesById);
+                var valuesById = {}, values = Object.create(valuesById);
                 values[valuesById[0] = "STRING"] = 0;
                 values[valuesById[1] = "CORD"] = 1;
                 values[valuesById[2] = "STRING_PIECE"] = 2;
@@ -11465,8 +11456,7 @@ $root.google = (function() {
              * @property {number} JS_NUMBER=2 JS_NUMBER value
              */
             FieldOptions.JSType = (function() {
-                var valuesById = {},
-                    values = Object.create(valuesById);
+                var valuesById = {}, values = Object.create(valuesById);
                 values[valuesById[0] = "JS_NORMAL"] = 0;
                 values[valuesById[1] = "JS_STRING"] = 1;
                 values[valuesById[2] = "JS_NUMBER"] = 2;
@@ -12567,8 +12557,7 @@ $root.google = (function() {
              * @property {number} IDEMPOTENT=2 IDEMPOTENT value
              */
             MethodOptions.IdempotencyLevel = (function() {
-                var valuesById = {},
-                    values = Object.create(valuesById);
+                var valuesById = {}, values = Object.create(valuesById);
                 values[valuesById[0] = "IDEMPOTENCY_UNKNOWN"] = 0;
                 values[valuesById[1] = "NO_SIDE_EFFECTS"] = 1;
                 values[valuesById[2] = "IDEMPOTENT"] = 2;