diff --git a/src/main.rs b/src/main.rs
index aec9a63..62f5d41 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -25,6 +25,7 @@ mod app;
 mod exec;
 mod internal;
 mod output;
+mod utils;
 mod walk;
 
 #[cfg(windows)]
@@ -152,7 +153,7 @@ fn main() {
                 .collect(),
         },
         extensions: matches.values_of("extension").map(|exts| {
-            exts.map(|e| e.trim_left_matches('.').to_lowercase())
+            exts.map(|e| String::from(".") + &e.trim_left_matches('.'))
                 .collect()
         }),
         command,
diff --git a/src/utils.rs b/src/utils.rs
new file mode 100644
index 0000000..f2c3926
--- /dev/null
+++ b/src/utils.rs
@@ -0,0 +1,45 @@
+// Copyright (c) 2017 fd developers
+// Licensed under the Apache License, Version 2.0
+// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0>
+// or the MIT license <LICENSE-MIT or http://opensource.org/licenses/MIT>,
+// at your option. All files in the project carrying such
+// notice may not be copied, modified, or distributed except
+// according to those terms.
+
+use std::path::Path;
+use std::iter::Iterator;
+
+/// Determine if an os string ends with any of the given extensions (case insensitive).
+pub fn path_has_any_extension<'a, I>(path: &Path, exts: I) -> bool
+where
+    I: 'a + Iterator<Item = &'a String> + Clone,
+{
+    // TODO: remove these two lines when we drop support for Rust version < 1.23.
+    #[allow(unused_imports)]
+    use std::ascii::AsciiExt;
+
+    if let Some(ref name) = path.file_name() {
+        if let Some(ref name_str) = name.to_str() {
+            exts.clone().any(|x| {
+                let mut it = name_str.chars().rev();
+
+                if x.chars()
+                    .rev()
+                    .zip(&mut it)
+                    .all(|(a, b)| a.eq_ignore_ascii_case(&b))
+                {
+                    match it.next() {
+                        Some('/') | None => false,
+                        _ => true,
+                    }
+                } else {
+                    false
+                }
+            })
+        } else {
+            false
+        }
+    } else {
+        false
+    }
+}
diff --git a/src/walk.rs b/src/walk.rs
index 8f18bf8..121d3a8 100644
--- a/src/walk.rs
+++ b/src/walk.rs
@@ -11,6 +11,7 @@ extern crate ctrlc;
 use exec;
 use fshelper;
 use internal::{error, FdOptions, EXITCODE_SIGINT, MAX_BUFFER_LENGTH};
+use utils::path_has_any_extension;
 use output;
 
 use std::process;
@@ -214,10 +215,7 @@ pub fn scan(path_vec: &[PathBuf], pattern: Arc<Regex>, config: Arc<FdOptions>) {
 
             // Filter out unwanted extensions.
             if let Some(ref filter_exts) = config.extensions {
-                let entry_ext = entry_path
-                    .extension()
-                    .map(|e| e.to_string_lossy().to_lowercase());
-                if entry_ext.map_or(true, |ext| !filter_exts.contains(&ext)) {
+                if !path_has_any_extension(entry_path, filter_exts.iter()) {
                     return ignore::WalkState::Continue;
                 }
             }
diff --git a/tests/tests.rs b/tests/tests.rs
index 3e80786..2e7e2b8 100644
--- a/tests/tests.rs
+++ b/tests/tests.rs
@@ -530,6 +530,28 @@ fn test_extension() {
     te.assert_output(&["--extension", ".foo", "a"], "a.foo");
 
     te.assert_output(&["--extension", "foo2"], "one/two/C.Foo2");
+
+    let te2 = TestEnv::new(&[], &["spam.bar.baz", "egg.bar.baz", "yolk.bar.baz.sig"]);
+
+    te2.assert_output(
+        &["--extension", ".bar.baz"],
+        "spam.bar.baz
+        egg.bar.baz",
+    );
+
+    te2.assert_output(&["--extension", "sig"], "yolk.bar.baz.sig");
+
+    te2.assert_output(&["--extension", "bar.baz.sig"], "yolk.bar.baz.sig");
+
+    let te3 = TestEnv::new(&[], &["latin1.e\u{301}xt", "smiley.☻"]);
+
+    te3.assert_output(&["--extension", "☻"], "smiley.☻");
+
+    te3.assert_output(&["--extension", ".e\u{301}xt"], "latin1.e\u{301}xt");
+
+    let te4 = TestEnv::new(&[], &[".hidden", "test.hidden"]);
+
+    te4.assert_output(&["--hidden", "--extension", ".hidden"], "test.hidden");
 }
 
 /// Symlinks misc