diff --git a/index.js b/index.js
index 42e1ddc..d86a68f 100644
--- a/index.js
+++ b/index.js
@@ -63,6 +63,10 @@ export function unflatten (target, opts) {
   // safely ensure that the key is
   // an integer.
   function getkey (key) {
+    // `Number('')` is 0 (not NaN), so an empty-string key would be coerced to
+    // the numeric index 0 and renamed; keep it as-is.
+    if (key === '') return key
+
     const parsedKey = Number(key)
 
     return (
diff --git a/test/test.js b/test/test.js
index ef01c9b..6c74eaf 100644
--- a/test/test.js
+++ b/test/test.js
@@ -566,6 +566,12 @@ describe('Arrays', function () {
     }))
   })
 
+  test('Should keep an empty-string key instead of renaming it to 0', function () {
+    assert.deepStrictEqual({ '': 1, x: 2 }, unflatten({ '': 1, x: 2 }))
+    assert.deepStrictEqual({ a: { '': 1 } }, unflatten({ 'a.': 1 }))
+    assert.deepStrictEqual({ '': 1, x: 2 }, unflatten(flatten({ '': 1, x: 2 })))
+  })
+
   test('Array typed objects should be restored by unflatten', function () {
     assert.strictEqual(
       Object.prototype.toString.call(['foo', 'bar'])