diff --git a/packages/babel-parser/src/parser/expression.js b/packages/babel-parser/src/parser/expression.js
index 04299e439830..79abd269e184 100644
--- a/packages/babel-parser/src/parser/expression.js
+++ b/packages/babel-parser/src/parser/expression.js
@@ -204,7 +204,10 @@ export default class ExpressionParser extends LValParser {
       node.left = this.match(tt.eq)
         ? this.toAssignable(left, undefined, "assignment expression")
         : left;
-      refShorthandDefaultPos.start = 0; // reset because shorthand default was used correctly
+
+      if (refShorthandDefaultPos.start >= node.left.start) {
+        refShorthandDefaultPos.start = 0; // reset because shorthand default was used correctly
+      }
 
       this.checkLVal(left, undefined, undefined, "assignment expression");
 
diff --git a/packages/babel-parser/test/fixtures/core/object/invalid-property-initializer-1/input.js b/packages/babel-parser/test/fixtures/core/object/invalid-property-initializer-1/input.js
new file mode 100644
index 000000000000..9538075c50c3
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/core/object/invalid-property-initializer-1/input.js
@@ -0,0 +1,4 @@
+const obj = {
+  bar: x = 123,
+  foo = 123
+};
diff --git a/packages/babel-parser/test/fixtures/core/object/invalid-property-initializer-1/options.json b/packages/babel-parser/test/fixtures/core/object/invalid-property-initializer-1/options.json
new file mode 100644
index 000000000000..e92fc4e28742
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/core/object/invalid-property-initializer-1/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Unexpected token (3:6)"
+}
diff --git a/packages/babel-parser/test/fixtures/core/object/invalid-property-initializer/input.js b/packages/babel-parser/test/fixtures/core/object/invalid-property-initializer/input.js
new file mode 100644
index 000000000000..868f237838df
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/core/object/invalid-property-initializer/input.js
@@ -0,0 +1,4 @@
+const obj = {
+  foo = 123,
+  bar: x = 123
+};
diff --git a/packages/babel-parser/test/fixtures/core/object/invalid-property-initializer/options.json b/packages/babel-parser/test/fixtures/core/object/invalid-property-initializer/options.json
new file mode 100644
index 000000000000..9660494a29ea
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/core/object/invalid-property-initializer/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "Unexpected token (2:6)"
+}
diff --git a/packages/babel-parser/test/fixtures/core/object/valid-property-initializer/input.js b/packages/babel-parser/test/fixtures/core/object/valid-property-initializer/input.js
new file mode 100644
index 000000000000..0cd0f5146c8d
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/core/object/valid-property-initializer/input.js
@@ -0,0 +1,4 @@
+const obj = {
+  foo = 123,
+  bar: x = 123,
+} = { foo: 24, bar: 45 };
diff --git a/packages/babel-parser/test/fixtures/core/object/valid-property-initializer/output.json b/packages/babel-parser/test/fixtures/core/object/valid-property-initializer/output.json
new file mode 100644
index 000000000000..7b1a47d91e7a
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/core/object/valid-property-initializer/output.json
@@ -0,0 +1,425 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 68,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 4,
+      "column": 25
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 68,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 4,
+        "column": 25
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start": 0,
+        "end": 68,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 4,
+            "column": 25
+          }
+        },
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start": 6,
+            "end": 67,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 6
+              },
+              "end": {
+                "line": 4,
+                "column": 24
+              }
+            },
+            "id": {
+              "type": "Identifier",
+              "start": 6,
+              "end": 9,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 6
+                },
+                "end": {
+                  "line": 1,
+                  "column": 9
+                },
+                "identifierName": "obj"
+              },
+              "name": "obj"
+            },
+            "init": {
+              "type": "AssignmentExpression",
+              "start": 12,
+              "end": 67,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 12
+                },
+                "end": {
+                  "line": 4,
+                  "column": 24
+                }
+              },
+              "operator": "=",
+              "left": {
+                "type": "ObjectPattern",
+                "start": 12,
+                "end": 44,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 12
+                  },
+                  "end": {
+                    "line": 4,
+                    "column": 1
+                  }
+                },
+                "properties": [
+                  {
+                    "type": "ObjectProperty",
+                    "start": 16,
+                    "end": 25,
+                    "loc": {
+                      "start": {
+                        "line": 2,
+                        "column": 2
+                      },
+                      "end": {
+                        "line": 2,
+                        "column": 11
+                      }
+                    },
+                    "method": false,
+                    "key": {
+                      "type": "Identifier",
+                      "start": 16,
+                      "end": 19,
+                      "loc": {
+                        "start": {
+                          "line": 2,
+                          "column": 2
+                        },
+                        "end": {
+                          "line": 2,
+                          "column": 5
+                        },
+                        "identifierName": "foo"
+                      },
+                      "name": "foo"
+                    },
+                    "computed": false,
+                    "shorthand": true,
+                    "value": {
+                      "type": "AssignmentPattern",
+                      "start": 16,
+                      "end": 25,
+                      "loc": {
+                        "start": {
+                          "line": 2,
+                          "column": 2
+                        },
+                        "end": {
+                          "line": 2,
+                          "column": 11
+                        }
+                      },
+                      "left": {
+                        "type": "Identifier",
+                        "start": 16,
+                        "end": 19,
+                        "loc": {
+                          "start": {
+                            "line": 2,
+                            "column": 2
+                          },
+                          "end": {
+                            "line": 2,
+                            "column": 5
+                          },
+                          "identifierName": "foo"
+                        },
+                        "name": "foo"
+                      },
+                      "right": {
+                        "type": "NumericLiteral",
+                        "start": 22,
+                        "end": 25,
+                        "loc": {
+                          "start": {
+                            "line": 2,
+                            "column": 8
+                          },
+                          "end": {
+                            "line": 2,
+                            "column": 11
+                          }
+                        },
+                        "extra": {
+                          "rawValue": 123,
+                          "raw": "123"
+                        },
+                        "value": 123
+                      }
+                    },
+                    "extra": {
+                      "shorthand": true
+                    }
+                  },
+                  {
+                    "type": "ObjectProperty",
+                    "start": 29,
+                    "end": 41,
+                    "loc": {
+                      "start": {
+                        "line": 3,
+                        "column": 2
+                      },
+                      "end": {
+                        "line": 3,
+                        "column": 14
+                      }
+                    },
+                    "method": false,
+                    "key": {
+                      "type": "Identifier",
+                      "start": 29,
+                      "end": 32,
+                      "loc": {
+                        "start": {
+                          "line": 3,
+                          "column": 2
+                        },
+                        "end": {
+                          "line": 3,
+                          "column": 5
+                        },
+                        "identifierName": "bar"
+                      },
+                      "name": "bar"
+                    },
+                    "computed": false,
+                    "shorthand": false,
+                    "value": {
+                      "type": "AssignmentPattern",
+                      "start": 34,
+                      "end": 41,
+                      "loc": {
+                        "start": {
+                          "line": 3,
+                          "column": 7
+                        },
+                        "end": {
+                          "line": 3,
+                          "column": 14
+                        }
+                      },
+                      "left": {
+                        "type": "Identifier",
+                        "start": 34,
+                        "end": 35,
+                        "loc": {
+                          "start": {
+                            "line": 3,
+                            "column": 7
+                          },
+                          "end": {
+                            "line": 3,
+                            "column": 8
+                          },
+                          "identifierName": "x"
+                        },
+                        "name": "x"
+                      },
+                      "right": {
+                        "type": "NumericLiteral",
+                        "start": 38,
+                        "end": 41,
+                        "loc": {
+                          "start": {
+                            "line": 3,
+                            "column": 11
+                          },
+                          "end": {
+                            "line": 3,
+                            "column": 14
+                          }
+                        },
+                        "extra": {
+                          "rawValue": 123,
+                          "raw": "123"
+                        },
+                        "value": 123
+                      }
+                    }
+                  }
+                ],
+                "extra": {
+                  "trailingComma": 41
+                }
+              },
+              "right": {
+                "type": "ObjectExpression",
+                "start": 47,
+                "end": 67,
+                "loc": {
+                  "start": {
+                    "line": 4,
+                    "column": 4
+                  },
+                  "end": {
+                    "line": 4,
+                    "column": 24
+                  }
+                },
+                "properties": [
+                  {
+                    "type": "ObjectProperty",
+                    "start": 49,
+                    "end": 56,
+                    "loc": {
+                      "start": {
+                        "line": 4,
+                        "column": 6
+                      },
+                      "end": {
+                        "line": 4,
+                        "column": 13
+                      }
+                    },
+                    "method": false,
+                    "key": {
+                      "type": "Identifier",
+                      "start": 49,
+                      "end": 52,
+                      "loc": {
+                        "start": {
+                          "line": 4,
+                          "column": 6
+                        },
+                        "end": {
+                          "line": 4,
+                          "column": 9
+                        },
+                        "identifierName": "foo"
+                      },
+                      "name": "foo"
+                    },
+                    "computed": false,
+                    "shorthand": false,
+                    "value": {
+                      "type": "NumericLiteral",
+                      "start": 54,
+                      "end": 56,
+                      "loc": {
+                        "start": {
+                          "line": 4,
+                          "column": 11
+                        },
+                        "end": {
+                          "line": 4,
+                          "column": 13
+                        }
+                      },
+                      "extra": {
+                        "rawValue": 24,
+                        "raw": "24"
+                      },
+                      "value": 24
+                    }
+                  },
+                  {
+                    "type": "ObjectProperty",
+                    "start": 58,
+                    "end": 65,
+                    "loc": {
+                      "start": {
+                        "line": 4,
+                        "column": 15
+                      },
+                      "end": {
+                        "line": 4,
+                        "column": 22
+                      }
+                    },
+                    "method": false,
+                    "key": {
+                      "type": "Identifier",
+                      "start": 58,
+                      "end": 61,
+                      "loc": {
+                        "start": {
+                          "line": 4,
+                          "column": 15
+                        },
+                        "end": {
+                          "line": 4,
+                          "column": 18
+                        },
+                        "identifierName": "bar"
+                      },
+                      "name": "bar"
+                    },
+                    "computed": false,
+                    "shorthand": false,
+                    "value": {
+                      "type": "NumericLiteral",
+                      "start": 63,
+                      "end": 65,
+                      "loc": {
+                        "start": {
+                          "line": 4,
+                          "column": 20
+                        },
+                        "end": {
+                          "line": 4,
+                          "column": 22
+                        }
+                      },
+                      "extra": {
+                        "rawValue": 45,
+                        "raw": "45"
+                      },
+                      "value": 45
+                    }
+                  }
+                ]
+              }
+            }
+          }
+        ],
+        "kind": "const"
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file