diff --git a/prboom2/src/SDL/i_video.c b/prboom2/src/SDL/i_video.c
index ac8fae201..055fa8757 100644
--- a/prboom2/src/SDL/i_video.c
+++ b/prboom2/src/SDL/i_video.c
@@ -361,19 +361,22 @@ static void I_GetEvent(void)
       case SDL_MOUSEWHEEL:
         if (mouse_enabled && window_focused)
         {
-          if (Event->wheel.y > 0)
-          {
-            event.data1.i = KEYD_MWHEELUP;
-
-            event.type = ev_keydown;
-            D_PostEvent(&event);
+          int mouseb;
 
-            event.type = ev_keyup;
-            D_PostEvent(&event);
-          }
+          if (Event->wheel.y > 0)
+            mouseb = KEYD_MWHEELUP;
           else if (Event->wheel.y < 0)
+            mouseb = KEYD_MWHEELDOWN;
+          else if (Event->wheel.x < 0)
+            mouseb = KEYD_MWHEELLEFT;
+          else if (Event->wheel.x > 0)
+            mouseb = KEYD_MWHEELRIGHT;
+          else
+            mouseb = 0;
+
+          if(mouseb)
           {
-            event.data1.i = KEYD_MWHEELDOWN;
+            event.data1.i = mouseb;
 
             event.type = ev_keydown;
             D_PostEvent(&event);
diff --git a/prboom2/src/doomdef.h b/prboom2/src/doomdef.h
index 1b71a57e2..c5b43c9b2 100644
--- a/prboom2/src/doomdef.h
+++ b/prboom2/src/doomdef.h
@@ -396,6 +396,8 @@ typedef enum {
 #define KEYD_MOUSE3     (0x80 + 0x62)
 #define KEYD_MWHEELUP   (0x80 + 0x6b)
 #define KEYD_MWHEELDOWN (0x80 + 0x6c)
+#define KEYD_MWHEELLEFT (0X80 + 0X6d)
+#define KEYD_MWHEELRIGHT (0X80 + 0X6e)
 
 // phares 3/20/98:
 //
diff --git a/prboom2/src/m_menu.c b/prboom2/src/m_menu.c
index f62e9a6ec..95b87eb10 100644
--- a/prboom2/src/m_menu.c
+++ b/prboom2/src/m_menu.c
@@ -3993,6 +3993,8 @@ int M_GetKeyString(int c,int offset)
       case KEYD_PAUSE:      s = "PAUS"; break;
       case KEYD_MWHEELDOWN: s = "MWDN"; break;
       case KEYD_MWHEELUP:   s = "MWUP"; break;
+      case KEYD_MWHEELLEFT: s = "MWLT"; break;
+      case KEYD_MWHEELRIGHT: s = "MWRT"; break;
       case KEYD_PRINTSC:    s = "PRSC"; break;
       case 0:               s = "NONE"; break;
       default:              s = "JUNK"; break;