diff --git a/src/libguac/guacamole/user-fntypes.h b/src/libguac/guacamole/user-fntypes.h
index 646a3b007..b9de901a3 100644
--- a/src/libguac/guacamole/user-fntypes.h
+++ b/src/libguac/guacamole/user-fntypes.h
@@ -220,12 +220,15 @@ typedef int guac_user_clipboard_handler(guac_user* user, guac_stream* stream,
  * @param height
  *     The desired height of the display, in pixels.
  *
+ * @param monitors
+ *     The count of monitors.
+ * 
  * @return
  *     Zero if the size event has been successfully handled, non-zero
  *     otherwise.
  */
 typedef int guac_user_size_handler(guac_user* user,
-        int width, int height);
+        int width, int height, int monitors);
 
 /**
  * Handler for Guacamole file streams received from a user. Each such file
diff --git a/src/libguac/guacamole/user.h b/src/libguac/guacamole/user.h
index 13fb146d4..4c041ab22 100644
--- a/src/libguac/guacamole/user.h
+++ b/src/libguac/guacamole/user.h
@@ -293,7 +293,7 @@ struct guac_user {
      *
      * Example:
      * @code
-     *     int size_handler(guac_user* user, int width, int height);
+     *     int size_handler(guac_user* user, int width, int height, int monitor);
      *
      *     int guac_user_init(guac_user* user, int argc, char** argv) {
      *         user->size_handler = size_handler;
diff --git a/src/libguac/user-handlers.c b/src/libguac/user-handlers.c
index b9013bc7c..450aa4892 100644
--- a/src/libguac/user-handlers.c
+++ b/src/libguac/user-handlers.c
@@ -372,7 +372,8 @@ int __guac_handle_size(guac_user* user, int argc, char** argv) {
         return user->size_handler(
             user,
             atoi(argv[0]), /* width */
-            atoi(argv[1])  /* height */
+            atoi(argv[1]), /* height */
+            (argc == 3 ? atoi(argv[2]) : 1) /* Monitors count */
         );
     return 0;
 }
diff --git a/src/protocols/kubernetes/input.c b/src/protocols/kubernetes/input.c
index b61d55643..dd2ada6fe 100644
--- a/src/protocols/kubernetes/input.c
+++ b/src/protocols/kubernetes/input.c
@@ -70,7 +70,7 @@ int guac_kubernetes_user_key_handler(guac_user* user, int keysym, int pressed) {
 
 }
 
-int guac_kubernetes_user_size_handler(guac_user* user, int width, int height) {
+int guac_kubernetes_user_size_handler(guac_user* user, int width, int height, int monitors) {
 
     /* Get terminal */
     guac_client* client = user->client;
diff --git a/src/protocols/rdp/channels/disp.c b/src/protocols/rdp/channels/disp.c
index da1ca800d..d72921d53 100644
--- a/src/protocols/rdp/channels/disp.c
+++ b/src/protocols/rdp/channels/disp.c
@@ -151,7 +151,7 @@ void guac_rdp_disp_load_plugin(rdpContext* context) {
 }
 
 void guac_rdp_disp_set_size(guac_rdp_disp* disp, guac_rdp_settings* settings,
-        freerdp* rdp_inst, int width, int height) {
+        freerdp* rdp_inst, int width, int height, int monitors) {
 
     guac_rect resize = {
         .left = 0,
diff --git a/src/protocols/rdp/input.c b/src/protocols/rdp/input.c
index d8890571e..4fc08bae5 100644
--- a/src/protocols/rdp/input.c
+++ b/src/protocols/rdp/input.c
@@ -191,7 +191,7 @@ int guac_rdp_user_key_handler(guac_user* user, int keysym, int pressed) {
 
 }
 
-int guac_rdp_user_size_handler(guac_user* user, int width, int height) {
+int guac_rdp_user_size_handler(guac_user* user, int width, int height, int monitors) {
 
     guac_client* client = user->client;
     guac_rdp_client* rdp_client = (guac_rdp_client*) client->data;
@@ -203,7 +203,7 @@ int guac_rdp_user_size_handler(guac_user* user, int width, int height) {
     height = height * settings->resolution / user->info.optimal_resolution;
 
     /* Send display update */
-    guac_rdp_disp_set_size(rdp_client->disp, settings, rdp_inst, width, height);
+    guac_rdp_disp_set_size(rdp_client->disp, settings, rdp_inst, width, height, monitors);
 
     return 0;
 
diff --git a/src/protocols/ssh/input.c b/src/protocols/ssh/input.c
index f60e1c9fa..07ab380a1 100644
--- a/src/protocols/ssh/input.c
+++ b/src/protocols/ssh/input.c
@@ -68,7 +68,7 @@ int guac_ssh_user_key_handler(guac_user* user, int keysym, int pressed) {
     return 0;
 }
 
-int guac_ssh_user_size_handler(guac_user* user, int width, int height) {
+int guac_ssh_user_size_handler(guac_user* user, int width, int height, int monitors) {
 
     /* Get terminal */
     guac_client* client = user->client;
diff --git a/src/protocols/telnet/input.c b/src/protocols/telnet/input.c
index 849d1897b..e79108363 100644
--- a/src/protocols/telnet/input.c
+++ b/src/protocols/telnet/input.c
@@ -120,7 +120,7 @@ int guac_telnet_user_key_handler(guac_user* user, int keysym, int pressed) {
 
 }
 
-int guac_telnet_user_size_handler(guac_user* user, int width, int height) {
+int guac_telnet_user_size_handler(guac_user* user, int width, int height, int monitors) {
 
     /* Get terminal */
     guac_client* client = user->client;
diff --git a/src/protocols/vnc/input.c b/src/protocols/vnc/input.c
index 04c80cf0a..4dea0a4ac 100644
--- a/src/protocols/vnc/input.c
+++ b/src/protocols/vnc/input.c
@@ -65,7 +65,7 @@ int guac_vnc_user_key_handler(guac_user* user, int keysym, int pressed) {
 }
 
 #ifdef LIBVNC_HAS_SIZE_MSG
-int guac_vnc_user_size_handler(guac_user* user, int width, int height) {
+int guac_vnc_user_size_handler(guac_user* user, int width, int height, int monitors) {
 
     guac_user_log(user, GUAC_LOG_TRACE, "Running user size handler.");