diff --git a/include/SDL_events.h b/include/SDL_events.h
index 0b848b944..fc5a145e7 100644
--- a/include/SDL_events.h
+++ b/include/SDL_events.h
@@ -257,8 +257,8 @@ typedef struct SDL_MouseWheelEvent
     Uint32 timestamp;
     Uint32 windowID;    /**< The window with mouse focus, if any */
     Uint32 which;       /**< The mouse instance id, or SDL_TOUCH_MOUSEID */
-    Sint32 x;           /**< The amount scrolled horizontally */
-    Sint32 y;           /**< The amount scrolled vertically */
+    Sint32 x;           /**< The amount scrolled horizontally, positive to the right and negative to the left */
+    Sint32 y;           /**< The amount scrolled vertically, positive away from the user and negative toward the user */
 } SDL_MouseWheelEvent;
 
 /**
diff --git a/src/video/cocoa/SDL_cocoamouse.m b/src/video/cocoa/SDL_cocoamouse.m
index 98b0e6161..56f679632 100644
--- a/src/video/cocoa/SDL_cocoamouse.m
+++ b/src/video/cocoa/SDL_cocoamouse.m
@@ -291,7 +291,7 @@ Cocoa_HandleMouseWheel(SDL_Window *window, NSEvent *event)
 {
     SDL_Mouse *mouse = SDL_GetMouse();
 
-    float x = [event deltaX];
+    float x = -[event deltaX];
     float y = [event deltaY];
 
     if (x > 0) {