diff --git a/include/constants/item_config.h b/include/constants/item_config.h
index eacad0af3..f9524e577 100644
--- a/include/constants/item_config.h
+++ b/include/constants/item_config.h
@@ -24,5 +24,6 @@
 #define P_NET_BALL_MODIFIER     GEN_7   // In Gen7+, Net Ball's catch multiplier is x5 instead of x3.
 #define P_NEST_BALL_MODIFIER    GEN_7   // Nest Ball's formula varies depending on the Gen. See Cmd_handleballthrow.
 #define P_REPEAT_BALL_MODIFIER  GEN_7   // In Gen7+, Net Ball's catch multiplier is x3.5 instead of x3.
+#define P_TIMER_BALL_MODIFIER   GEN_7   // In Gen5+, Timer Ball's effectiveness increases by x0.3 per turn instead of x0.1
 
 #endif // GUARD_CONSTANTS_ITEM_CONFIG_H
diff --git a/src/battle_script_commands.c b/src/battle_script_commands.c
index 6f07c6bca..a5895cbc7 100644
--- a/src/battle_script_commands.c
+++ b/src/battle_script_commands.c
@@ -9824,7 +9824,11 @@ static void Cmd_handleballthrow(void)
                     #endif
                 break;
             case ITEM_TIMER_BALL:
-                ballMultiplier = gBattleResults.battleTurnCounter + 10;
+                #if P_TIMER_BALL_MODIFIER >= GEN_5
+                    ballMultiplier = (gBattleResults.battleTurnCounter * 3) + 10;
+                #else
+                    ballMultiplier = gBattleResults.battleTurnCounter + 10;
+                #endif
                 if (ballMultiplier > 40)
                     ballMultiplier = 40;
                 break;