diff --git a/README.md b/README.md
index bf53c31b87..269c0bf5da 100644
--- a/README.md
+++ b/README.md
@@ -132,6 +132,11 @@ object referring to that same position.
 - **directSourceFile**: Like `sourceFile`, but a `sourceFile` property
   will be added directly to the nodes, rather than the `loc` object.
 
+- **preserveParens**: If this option is `true`, parenthesized expressions
+  are represented by (non-standard) `ParenthesizedExpression` nodes
+  that have a single `expression` property containing the expression
+  inside parentheses.
+
 [range]: https://bugzilla.mozilla.org/show_bug.cgi?id=745678
 
 **parseExpressionAt**`(input, offset, options)` will parse a single
diff --git a/acorn.js b/acorn.js
index 2da669c499..2d740e8c50 100644
--- a/acorn.js
+++ b/acorn.js
@@ -112,7 +112,10 @@
     sourceFile: null,
     // This value, if given, is stored in every node, whether
     // `locations` is on or off.
-    directSourceFile: null
+    directSourceFile: null,
+    // When enabled, parenthesized expressions are represented by
+    // (non-standard) ParenthesizedExpression nodes
+    preserveParens: false
   };
 
   // This function tries to parse a single expression at a given
@@ -1459,6 +1462,10 @@
       case "SpreadElement":
         break;
 
+      case "ParenthesizedExpression":
+        checkLVal(expr.expression);
+        break;
+
       default:
         raise(expr.start, "Assigning to rvalue");
     }
@@ -2041,6 +2048,12 @@
               if (exprList[i].type === "SpreadElement") unexpected();
             }
           }
+
+          if (options.preserveParens) {
+            var par = startNodeAt(start);
+            par.expression = val;
+            val = finishNode(par, "ParenthesizedExpression");
+          }
         }
       }
       return val;
diff --git a/test/tests-harmony.js b/test/tests-harmony.js
index 01010e95ca..1a883ee051 100644
--- a/test/tests-harmony.js
+++ b/test/tests-harmony.js
@@ -15391,3 +15391,25 @@ test('function normal(x, y = 10) {}', {
 }, {ecmaVersion: 6});
 
 test("'use strict'; function f([x,,z]) {}", {}, {ecmaVersion: 6});
+
+// test preserveParens option with arrow functions
+test("() => 42", {
+  type: "Program",
+  body: [{
+    type: "ExpressionStatement",
+    expression: {
+      type: "ArrowFunctionExpression"
+    }
+  }]
+}, {ecmaVersion: 6, preserveParens: true});
+
+// test preserveParens with generators
+test("(for (x of array) for (y of array2) if (x === test) x)", {
+  type: "Program",
+  body: [{
+    type: "ExpressionStatement",
+    expression: {
+      type: "ComprehensionExpression"
+    }
+  }]
+}, {ecmaVersion: 6, preserveParens: true});
diff --git a/test/tests.js b/test/tests.js
index 5a86572a93..4fedc72ca1 100644
--- a/test/tests.js
+++ b/test/tests.js
@@ -234,6 +234,123 @@ test("(1 + 2 ) * 3", {
   }
 });
 
+test("(1 + 2 ) * 3", {
+  type: "Program",
+  body: [
+    {
+      type: "ExpressionStatement",
+      expression: {
+        type: "BinaryExpression",
+        left: {
+          type: "ParenthesizedExpression",
+          expression: {
+            type: "BinaryExpression",
+            left: {
+              type: "Literal",
+              value: 1,
+              loc: {
+                start: {
+                  line: 1,
+                  column: 1
+                },
+                end: {
+                  line: 1,
+                  column: 2
+                }
+              }
+            },
+            operator: "+",
+            right: {
+              type: "Literal",
+              value: 2,
+              loc: {
+                start: {
+                  line: 1,
+                  column: 5
+                },
+                end: {
+                  line: 1,
+                  column: 6
+                }
+              }
+            },
+            loc: {
+              start: {
+                line: 1,
+                column: 1
+              },
+              end: {
+                line: 1,
+                column: 6
+              }
+            }
+          },
+          loc: {
+            start: {
+              line: 1,
+              column: 0
+            },
+            end: {
+              line: 1,
+              column: 8
+            }
+          }
+        },
+        operator: "*",
+        right: {
+          type: "Literal",
+          value: 3,
+          loc: {
+            start: {
+              line: 1,
+              column: 11
+            },
+            end: {
+              line: 1,
+              column: 12
+            }
+          }
+        },
+        loc: {
+          start: {
+            line: 1,
+            column: 0
+          },
+          end: {
+            line: 1,
+            column: 12
+          }
+        }
+      },
+      loc: {
+        start: {
+          line: 1,
+          column: 0
+        },
+        end: {
+          line: 1,
+          column: 12
+        }
+      }
+    }
+  ],
+  loc: {
+    start: {
+      line: 1,
+      column: 0
+    },
+    end: {
+      line: 1,
+      column: 12
+    }
+  }
+}, {
+  locations: true,
+  preserveParens: true
+});
+
+test("(x) = 23", {}, { preserveParens: true });
+
 test("x = []", {
   type: "Program",
   body: [