diff --git a/CHANGELOG.md b/CHANGELOG.md
index 582e49d1..51928c03 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,14 @@ All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [ Unreleased ] - ReleaseDate
+
+## Fixed
+
+- Fixed using Mockall when a function named `Ok` is in scope.  The `anyhow`
+  crate, for example, creates a function by this name.
+  ([#389](https://github.com/asomers/mockall/pull/389))
+
 ## [ 0.11.1 ] - 2022-05-15
 
 ### Fixed
diff --git a/mockall/tests/anyhow.rs b/mockall/tests/anyhow.rs
new file mode 100644
index 00000000..7d400931
--- /dev/null
+++ b/mockall/tests/anyhow.rs
@@ -0,0 +1,86 @@
+// vim: tw=80
+//! Mockall should be compatible with crates like Anyhow that redefine `Ok`.
+#![deny(warnings)]
+
+use mockall::*;
+
+// Define Error, Result, and Ok similarly to how anyhow defines them
+pub struct Error();
+impl Error {
+    pub fn new<E: std::error::Error>(_e: E) -> Self {
+        Self()
+    }
+}
+#[allow(non_snake_case)]
+pub fn Ok<T>(t: T) -> Result<T> {
+    Result::Ok(t)
+}
+pub type Result<T, E = Error> = std::result::Result<T, E>;
+
+#[automock]
+trait Foo {
+    fn foo(&self) -> Result<(), Error>;
+    fn reffoo(&self) -> &Result<(), Error>;
+    fn refmutfoo(&mut self) -> &mut Result<(), Error>;
+    fn staticfoo() -> Result<(), Error>;
+}
+
+mod static_method {
+    use super::*;
+
+    #[test]
+    fn ok() {
+        let mut foo = MockFoo::new();
+        foo.expect_foo()
+            .returning(|| Ok(()));
+        assert!(foo.foo().is_ok());
+    }
+
+    #[test]
+    fn err() {
+        let mut foo = MockFoo::new();
+        foo.expect_foo()
+            .returning(|| Err(Error::new(std::io::Error::last_os_error())));
+        assert!(foo.foo().is_err());
+    }
+}
+
+mod ref_method {
+    use super::*;
+
+    #[test]
+    fn ok() {
+        let mut foo = MockFoo::new();
+        foo.expect_reffoo()
+            .return_const(Ok(()));
+        assert!(foo.reffoo().is_ok());
+    }
+
+    #[test]
+    fn err() {
+        let mut foo = MockFoo::new();
+        foo.expect_reffoo()
+            .return_const(Err(Error::new(std::io::Error::last_os_error())));
+        assert!(foo.reffoo().is_err());
+    }
+}
+
+mod refmut_method {
+    use super::*;
+
+    #[test]
+    fn ok() {
+        let mut foo = MockFoo::new();
+        foo.expect_refmutfoo()
+            .return_var(Ok(()));
+        assert!(foo.refmutfoo().is_ok());
+    }
+
+    #[test]
+    fn err() {
+        let mut foo = MockFoo::new();
+        foo.expect_refmutfoo()
+            .return_var(Err(Error::new(std::io::Error::last_os_error())));
+        assert!(foo.refmutfoo().is_err());
+    }
+}
diff --git a/mockall_derive/src/mock_function.rs b/mockall_derive/src/mock_function.rs
index 78df187c..8de62080 100644
--- a/mockall_derive/src/mock_function.rs
+++ b/mockall_derive/src/mock_function.rs
@@ -1647,13 +1647,13 @@ impl<'a> ToTokens for RefRfunc<'a> {
                 {
                     match self {
                         Rfunc::Default(Some(ref __mockall_o)) => {
-                            Ok(__mockall_o)
+                            ::std::result::Result::Ok(__mockall_o)
                         },
                         Rfunc::Default(None) => {
                             Err(#default_err_msg)
                         },
                         Rfunc::Const(ref __mockall_o) => {
-                            Ok(__mockall_o)
+                            ::std::result::Result::Ok(__mockall_o)
                         },
                         Rfunc::_Phantom(_) => unreachable!()
                     }
@@ -1717,7 +1717,7 @@ impl<'a> ToTokens for RefMutRfunc<'a> {
                 {
                     match self {
                         Rfunc::Default(Some(ref mut __mockall_o)) => {
-                            Ok(__mockall_o)
+                            ::std::result::Result::Ok(__mockall_o)
                         },
                         Rfunc::Default(None) => {
                             Err(#default_err_msg)
@@ -1726,7 +1726,7 @@ impl<'a> ToTokens for RefMutRfunc<'a> {
                         {
                             *__mockall_o = Some(__mockall_f(#(#argnames, )*));
                             if let Some(ref mut __mockall_o2) = __mockall_o {
-                                Ok(__mockall_o2)
+                                ::std::result::Result::Ok(__mockall_o2)
                             } else {
                                 unreachable!()
                             }
@@ -1737,13 +1737,13 @@ impl<'a> ToTokens for RefMutRfunc<'a> {
                                     #(#argnames, )*)
                             );
                             if let Some(ref mut __mockall_o2) = __mockall_o {
-                                Ok(__mockall_o2)
+                                ::std::result::Result::Ok(__mockall_o2)
                             } else {
                                 unreachable!()
                             }
                         },
                         Rfunc::Var(ref mut __mockall_o) => {
-                            Ok(__mockall_o)
+                            ::std::result::Result::Ok(__mockall_o)
                         },
                         Rfunc::_Phantom(_) => unreachable!()
                     }
@@ -1812,15 +1812,15 @@ impl<'a> ToTokens for StaticRfunc<'a> {
                             Err("called twice, but it returns by move")
                         },
                         Rfunc::Mut(__mockall_f) => {
-                            Ok(__mockall_f( #(#argnames, )* ))
+                            ::std::result::Result::Ok(__mockall_f( #(#argnames, )* ))
                         },
                         Rfunc::MutSt(__mockall_f) => {
-                            Ok((__mockall_f.get_mut())(#(#argnames,)*))
+                            ::std::result::Result::Ok((__mockall_f.get_mut())(#(#argnames,)*))
                         },
                         Rfunc::Once(_) => {
                             if let Rfunc::Once(mut __mockall_f) =
                                 mem::replace(self, Rfunc::Expired) {
-                                Ok(__mockall_f( #(#argnames, )* ))
+                                ::std::result::Result::Ok(__mockall_f( #(#argnames, )* ))
                             } else {
                                 unreachable!()
                             }
@@ -1828,7 +1828,7 @@ impl<'a> ToTokens for StaticRfunc<'a> {
                         Rfunc::OnceSt(_) => {
                             if let Rfunc::OnceSt(mut __mockall_f) =
                                 mem::replace(self, Rfunc::Expired) {
-                                Ok((__mockall_f.into_inner())(#(#argnames,)*))
+                                ::std::result::Result::Ok((__mockall_f.into_inner())(#(#argnames,)*))
                             } else {
                                 unreachable!()
                             }