diff --git a/examples/srv_accept_unmasked_frames.rs b/examples/srv_accept_unmasked_frames.rs
new file mode 100644
index 0000000..953f9f1
--- /dev/null
+++ b/examples/srv_accept_unmasked_frames.rs
@@ -0,0 +1,50 @@
+use std::{net::TcpListener, thread::spawn};
+use tungstenite::{
+    handshake::server::{Request, Response},
+    protocol::WebSocketConfig,
+    server::accept_hdr_with_config,
+};
+
+fn main() {
+    env_logger::init();
+    let server = TcpListener::bind("127.0.0.1:3012").unwrap();
+    for stream in server.incoming() {
+        spawn(move || {
+            let callback = |req: &Request, mut response: Response| {
+                println!("Received a new ws handshake");
+                println!("The request's path is: {}", req.uri().path());
+                println!("The request's headers are:");
+                for (ref header, _value) in req.headers() {
+                    println!("* {}", header);
+                }
+
+                // Let's add an additional header to our response to the client.
+                let headers = response.headers_mut();
+                headers.append("MyCustomHeader", ":)".parse().unwrap());
+                headers.append("SOME_TUNGSTENITE_HEADER", "header_value".parse().unwrap());
+
+                Ok(response)
+            };
+
+            let config = Some(WebSocketConfig {
+                max_send_queue: None,
+                max_message_size: None,
+                max_frame_size: None,
+                // This setting allows to accept client frames which are not masked
+                // This is not in compliance with RFC 6455 but might be handy in some
+                // rare cases where it is necessary to integrate with existing/legacy
+                // clients which are sending unmasked frames
+                accept_unmasked_frames: true,
+            });
+
+            let mut websocket = accept_hdr_with_config(stream.unwrap(), callback, config).unwrap();
+
+            loop {
+                let msg = websocket.read_message().unwrap();
+                if msg.is_binary() || msg.is_text() {
+                    println!("received message {}", msg);
+                }
+            }
+        });
+    }
+}
diff --git a/src/protocol/mod.rs b/src/protocol/mod.rs
index 72485e9..63763f0 100644
--- a/src/protocol/mod.rs
+++ b/src/protocol/mod.rs
@@ -50,6 +50,12 @@ pub struct WebSocketConfig {
     /// be reasonably big for all normal use-cases but small enough to prevent memory eating
     /// by a malicious user.
     pub max_frame_size: Option<usize>,
+    /// When set to `true`, the server will accept and handle unmasked frames
+    /// from the client. According to the RFC 6455, the server must close the
+    /// connection to the client in such cases, however it seems like there are
+    /// some popular libraries that are sending unmasked frames, ignoring the RFC.
+    /// By default this option is set to `false`, i.e. according to RFC 6455.
+    pub accept_unmasked_frames: bool,
 }
 
 impl Default for WebSocketConfig {
@@ -58,6 +64,7 @@ impl Default for WebSocketConfig {
             max_send_queue: None,
             max_message_size: Some(64 << 20),
             max_frame_size: Some(16 << 20),
+            accept_unmasked_frames: false,
         }
     }
 }
@@ -446,9 +453,11 @@ impl WebSocketContext {
                         // A server MUST remove masking for data frames received from a client
                         // as described in Section 5.3. (RFC 6455)
                         frame.apply_mask()
-                    } else {
+                    } else if !self.config.accept_unmasked_frames {
                         // The server MUST close the connection upon receiving a
                         // frame that is not masked. (RFC 6455)
+                        // The only exception here is if the user explicitly accepts given
+                        // stream by setting WebSocketConfig.accept_unmasked_frames to true
                         return Err(Error::Protocol(
                             "Received an unmasked frame from client".into(),
                         ));