diff --git a/mock/mock.go b/mock/mock.go
index f0af8246c..a64e8fbcc 100644
--- a/mock/mock.go
+++ b/mock/mock.go
@@ -243,7 +243,7 @@ func (c *Call) Unset() *Call {
 // calls have been called as expected. The referenced calls may be from the
 // same mock instance and/or other mock instances.
 //
-//     Mock.On("Do").Return(nil).Notbefore(
+//     Mock.On("Do").Return(nil).NotBefore(
 //         Mock.On("Init").Return(nil)
 //     )
 func (c *Call) NotBefore(calls ...*Call) *Call {