diff --git a/src/libguac/guacamole/protocol.h b/src/libguac/guacamole/protocol.h
index 409a4083ea..1a690d1c04 100644
--- a/src/libguac/guacamole/protocol.h
+++ b/src/libguac/guacamole/protocol.h
@@ -1155,5 +1155,44 @@ guac_protocol_version guac_protocol_string_to_version(const char* version_string
  */
 const char* guac_protocol_version_to_string(guac_protocol_version version);
 
-#endif
+/**
+ * Sends a usbdisconnect instruction over the given guac_socket connection,
+ * requesting that the client disconnect the specified USB device.
+ *
+ * @param socket
+ *     The guac_socket connection to use.
+ *
+ * @param device_id
+ *     The unique identifier of the USB device that should be disconnected.
+ *
+ * @return
+ *     Zero on success, non-zero on error.
+ */
+int guac_protocol_send_usbdisconnect(guac_socket* socket, 
+        const char* device_id);
+
+/**
+ * Sends a usbdata instruction over the given guac_socket connection,
+ * sending USB data to a specific endpoint on a client-side USB device.
+ *
+ * @param socket
+ *     The guac_socket connection to use.
+ *
+ * @param device_id
+ *     The unique identifier of the USB device.
+ *
+ * @param endpoint_number
+ *     The USB endpoint number identifying the logical communication channel
+ *     for this data transfer. The valid endpoint numbers for a device are
+ *     provided in the interface_data parameter during usbconnect.
+ *
+ * @param data
+ *     The base64-encoded data to send to the USB device.
+ *
+ * @return
+ *     Zero on success, non-zero on error.
+ */
+int guac_protocol_send_usbdata(guac_socket* socket, const char* device_id,
+        int endpoint_number, const char* data);
 
+#endif
diff --git a/src/libguac/guacamole/user-fntypes.h b/src/libguac/guacamole/user-fntypes.h
index 646a3b0076..fa3cac6f8e 100644
--- a/src/libguac/guacamole/user-fntypes.h
+++ b/src/libguac/guacamole/user-fntypes.h
@@ -499,5 +499,95 @@ typedef int guac_user_get_handler(guac_user* user, guac_object* object,
 typedef int guac_user_put_handler(guac_user* user, guac_object* object,
         guac_stream* stream, char* mimetype, char* name);
 
-#endif
+/**
+ * Handler for Guacamole USB connect events, invoked when a "usbconnect" 
+ * instruction has been received from a user. This indicates that the user
+ * has connected a USB device via WebUSB and it is available for redirection.
+ *
+ * @param device_id
+ *     The unique identifier for the USB device. Required.
+ *
+ * @param vendor_id
+ *     The vendor ID of the USB device. Required.
+ *
+ * @param product_id
+ *     The product ID of the USB device. Required.
+ *
+ * @param device_name
+ *     The human-readable name of the device. Required (may be empty string).
+ *
+ * @param serial_number
+ *     The serial number of the device. Optional (may be NULL or empty string
+ *     if not available).
+ *
+ * @param device_class
+ *     The USB device class. Required.
+ *
+ * @param device_subclass
+ *     The USB device subclass. Required.
+ *
+ * @param device_protocol
+ *     The USB device protocol. Required.
+ *
+ * @param interface_data
+ *     Encoded string containing interface and endpoint information. Required.
+ *     Format: "ifaceNum:class:subclass:protocol:ep1Num:ep1Dir:ep1Type:ep1Size;ep2...,iface2..."
+ *     where multiple endpoints within an interface are separated by semicolons
+ *     and multiple interfaces are separated by commas.
+ *
+ * @return
+ *     Zero if the USB connect event was handled successfully, or non-zero if 
+ *     an error occurred.
+ */
+typedef int guac_user_usbconnect_handler(guac_user* user, const char* device_id,
+    int vendor_id, int product_id, const char* device_name, 
+    const char* serial_number, int device_class, int device_subclass,
+    int device_protocol, const char* interface_data);
 
+/**
+* Handler for Guacamole USB data events, invoked when a "usbdata" instruction
+* has been received from a user. This carries data from a client-side USB 
+* device to be processed on the server side.
+*
+* @param user
+*     The user that sent the USB data.
+*
+* @param device_id
+*     The unique identifier for the USB device.
+*
+* @param endpoint_number
+*     The USB endpoint number that the data originated from. Endpoint
+*     numbers correspond to the endpoints defined in the device's
+*     interface_data from the usbconnect instruction.
+*
+* @param data
+*     The base64-encoded USB data.
+*
+* @param transfer_type
+*     The type of USB transfer (bulk, interrupt, isochronous, control).
+*
+* @return
+*     Zero if the USB data was handled successfully, or non-zero if an error
+*     occurred.
+*/
+typedef int guac_user_usbdata_handler(guac_user* user, const char* device_id,
+    int endpoint_number, const char* data, const char* transfer_type);
+
+/**
+* Handler for Guacamole USB disconnect events, invoked when a "usbdisconnect"
+* instruction has been received from a user. This indicates that the user
+* has disconnected a USB device that was previously available for redirection.
+*
+* @param user
+*     The user that disconnected the USB device.
+*
+* @param device_id
+*     The unique identifier for the USB device that was disconnected.
+*
+* @return
+*     Zero if the USB disconnect event was handled successfully, or non-zero 
+*     if an error occurred.
+*/
+typedef int guac_user_usbdisconnect_handler(guac_user* user, const char* device_id);
+
+#endif
diff --git a/src/libguac/guacamole/user.h b/src/libguac/guacamole/user.h
index 13fb146d4d..fa251944d7 100644
--- a/src/libguac/guacamole/user.h
+++ b/src/libguac/guacamole/user.h
@@ -538,6 +538,66 @@ struct guac_user {
      */
     guac_user_touch_handler* touch_handler;
 
+/**
+     * Handler for USB connect events sent by the Guacamole web-client.
+     *
+     * The handler takes the user that connected the device, the device ID
+     * (required), vendor ID (required), product ID (required), device name
+     * (required), serial number (optional - may be NULL or empty), device class
+     * (required), device subclass (required), device protocol (required), and
+     * interface data (required).
+     *
+     * Example:
+     * @code
+     *     int usbconnect_handler(guac_user* user, const char* device_id,
+     *             int vendor_id, int product_id, const char* device_name,
+     *             const char* serial_number, int device_class, 
+     *             int device_subclass, int device_protocol, 
+     *             const char* interface_data);
+     *
+     *     int guac_user_init(guac_user* user, int argc, char** argv) {
+     *         user->usbconnect_handler = usbconnect_handler;
+     *     }
+     * @endcode
+     */
+    guac_user_usbconnect_handler* usbconnect_handler;
+
+    /**
+     * Handler for USB data events sent by the Guacamole web-client.
+     *
+     * The handler takes the user that sent the data, the device ID,
+     * endpoint number, the base64-encoded data, and the transfer type.
+     *
+     * Example:
+     * @code
+     *     int usbdata_handler(guac_user* user, const char* device_id,
+     *             int endpoint_number, const char* data,
+     *             const char* transfer_type);
+     *
+     *     int guac_user_init(guac_user* user, int argc, char** argv) {
+     *         user->usbdata_handler = usbdata_handler;
+     *     }
+     * @endcode
+     */
+    guac_user_usbdata_handler* usbdata_handler;
+
+    /**
+     * Handler for USB disconnect events sent by the Guacamole web-client.
+     *
+     * The handler takes the user that disconnected the device and the
+     * device ID.
+     *
+     * Example:
+     * @code
+     *     int usbdisconnect_handler(guac_user* user, const char* device_id);
+     *
+     *     int guac_user_init(guac_user* user, int argc, char** argv) {
+     *         user->usbdisconnect_handler = usbdisconnect_handler;
+     *     }
+     * @endcode
+     */
+    guac_user_usbdisconnect_handler* usbdisconnect_handler;
+
 };
 
 /**
@@ -1002,4 +1062,3 @@ int guac_user_parse_args_boolean(guac_user* user, const char** arg_names,
         const char** argv, int index, int default_value);
 
 #endif
-
diff --git a/src/libguac/protocol.c b/src/libguac/protocol.c
index b415dac8af..b634a8abc6 100644
--- a/src/libguac/protocol.c
+++ b/src/libguac/protocol.c
@@ -1406,3 +1406,38 @@ const char* guac_protocol_version_to_string(guac_protocol_version version) {
     
 }
 
+int guac_protocol_send_usbdisconnect(guac_socket* socket, 
+        const char* device_id) {
+
+    int ret_val;
+
+    guac_socket_instruction_begin(socket);
+    ret_val =
+           guac_socket_write_string(socket, "13.usbdisconnect,")
+        || __guac_socket_write_length_string(socket, device_id)
+        || guac_socket_write_string(socket, ";");
+
+    guac_socket_instruction_end(socket);
+    return ret_val;
+
+}
+
+int guac_protocol_send_usbdata(guac_socket* socket, const char* device_id,
+        int endpoint_number, const char* data) {
+
+    int ret_val;
+
+    guac_socket_instruction_begin(socket);
+    ret_val =
+           guac_socket_write_string(socket, "7.usbdata,")
+        || __guac_socket_write_length_string(socket, device_id)
+        || guac_socket_write_string(socket, ",")
+        || __guac_socket_write_length_int(socket, endpoint_number)
+        || guac_socket_write_string(socket, ",")
+        || __guac_socket_write_length_string(socket, data)
+        || guac_socket_write_string(socket, ";");
+
+    guac_socket_instruction_end(socket);
+    return ret_val;
+
+}
\ No newline at end of file
diff --git a/src/libguac/user-handlers.c b/src/libguac/user-handlers.c
index b9013bc7c2..179bac76b0 100644
--- a/src/libguac/user-handlers.c
+++ b/src/libguac/user-handlers.c
@@ -55,6 +55,9 @@ __guac_instruction_handler_mapping __guac_instruction_handler_map[] = {
    {"audio",      __guac_handle_audio},
    {"argv",       __guac_handle_argv},
    {"nop",        __guac_handle_nop},
+   {"usbconnect",    __guac_handle_usbconnect},
+   {"usbdata",       __guac_handle_usbdata},
+   {"usbdisconnect", __guac_handle_usbdisconnect},
    {NULL,         NULL}
 };
 
@@ -627,6 +630,83 @@ int __guac_handle_disconnect(guac_user* user, int argc, char** argv) {
     return 0;
 }
 
+int __guac_handle_usbconnect(guac_user* user, int argc, char** argv) {
+
+    if (argc != 9) {
+        guac_user_log(user, GUAC_LOG_WARNING, "Received \"usbconnect\" "
+                "instruction with wrong number of arguments (expected 9, got %d).", 
+                argc);
+        return 0;
+    }
+
+    if (user->usbconnect_handler)
+        return user->usbconnect_handler(
+            user,
+            argv[0], /* device_id */
+            atoi(argv[1]), /* vendor_id */
+            atoi(argv[2]), /* product_id */
+            argv[3], /* device_name */
+            argv[4], /* serial_number */
+            atoi(argv[5]), /* device_class */
+            atoi(argv[6]), /* device_subclass */
+            atoi(argv[7]), /* device_protocol */
+            argv[8]  /* interface_data */
+        );
+
+    guac_user_log(user, GUAC_LOG_DEBUG, "USB redirection not supported, "
+            "ignoring usbconnect instruction.");
+    return 0;
+
+}
+
+int __guac_handle_usbdata(guac_user* user, int argc, char** argv) {
+
+    if (argc != 4) {
+        guac_user_log(user, GUAC_LOG_WARNING, "Received \"usbdata\" "
+                "instruction with wrong number of arguments (expected 4, got %d).", 
+                argc);
+        return 0;
+    }
+
+    if (user->usbdata_handler) {
+        /* Decode base64 data */
+        guac_protocol_decode_base64(argv[2]);
+        return user->usbdata_handler(
+            user,
+            argv[0], /* device_id */
+            atoi(argv[1]), /* endpoint_number */
+            argv[2], /* data (now decoded) */
+            argv[3]  /* transfer_type */
+        );
+    }
+
+    guac_user_log(user, GUAC_LOG_DEBUG, "USB redirection not supported, "
+            "ignoring usbdata instruction.");
+    return 0;
+
+}
+
+int __guac_handle_usbdisconnect(guac_user* user, int argc, char** argv) {
+
+    if (argc != 1) {
+        guac_user_log(user, GUAC_LOG_WARNING, "Received \"usbdisconnect\" "
+                "instruction with wrong number of arguments (expected 1, got %d).", 
+                argc);
+        return 0;
+    }
+
+    if (user->usbdisconnect_handler)
+        return user->usbdisconnect_handler(
+            user,
+            argv[0] /* device_id */
+        );
+
+    guac_user_log(user, GUAC_LOG_DEBUG, "USB redirection not supported, "
+            "ignoring usbdisconnect instruction.");
+    return 0;
+
+}
+
 /* Guacamole handshake handler functions. */
 
 int __guac_handshake_size_handler(guac_user* user, int argc, char** argv) {
@@ -777,4 +857,3 @@ int __guac_user_call_opcode_handler(__guac_instruction_handler_mapping* map,
     return 0;
 
 }
-
diff --git a/src/libguac/user-handlers.h b/src/libguac/user-handlers.h
index 2f3ecbe9b3..c55d667810 100644
--- a/src/libguac/user-handlers.h
+++ b/src/libguac/user-handlers.h
@@ -231,6 +231,27 @@ __guac_instruction_handler __guac_handshake_name_handler;
  */
 __guac_instruction_handler __guac_handshake_timezone_handler;
 
+/**
+ * Internal initial handler for the usbconnect instruction. When a usbconnect
+ * instruction is received, this handler will be called. The user's
+ * usbconnect handler will be invoked if defined.
+ */
+__guac_instruction_handler __guac_handle_usbconnect;
+
+/**
+ * Internal initial handler for the usbdata instruction. When a usbdata
+ * instruction is received, this handler will be called. The user's
+ * usbdata handler will be invoked if defined.
+ */
+__guac_instruction_handler __guac_handle_usbdata;
+
+/**
+ * Internal initial handler for the usbdisconnect instruction. When a 
+ * usbdisconnect instruction is received, this handler will be called. 
+ * The user's usbdisconnect handler will be invoked if defined.
+ */
+__guac_instruction_handler __guac_handle_usbdisconnect;
+
 /**
  * Instruction handler mapping table. This is a NULL-terminated array of
  * __guac_instruction_handler_mapping structures, each mapping an opcode