diff --git a/src/battle_ai_main.c b/src/battle_ai_main.c
index 5fc7e3fcbf..abe8cbf696 100644
--- a/src/battle_ai_main.c
+++ b/src/battle_ai_main.c
@@ -640,6 +640,7 @@ void SetAiLogicDataForTurn(struct AiLogicData *aiData)
     u32 battlerAtk, battlersCount, weather;
 
     memset(aiData, 0, sizeof(struct AiLogicData));
+    gAiBattleData->aiUsingGimmick = 0;
     if (!(gBattleTypeFlags & BATTLE_TYPE_HAS_AI) && !IsWildMonSmart())
         return;
 
diff --git a/src/battle_ai_switch_items.c b/src/battle_ai_switch_items.c
index 7d150d1a3b..c04b22d417 100644
--- a/src/battle_ai_switch_items.c
+++ b/src/battle_ai_switch_items.c
@@ -1351,6 +1351,7 @@ void AI_TrySwitchOrUseItem(u32 battler)
         if (gAiLogicData->shouldSwitch & (1u << battler) && IsSwitchinValid(battler))
         {
             BtlController_EmitTwoReturnValues(battler, B_COMM_TO_ENGINE, B_ACTION_SWITCH, 0);
+            SetAIUsingGimmick(battler, NO_GIMMICK);
             if (gBattleStruct->AI_monToSwitchIntoId[battler] == PARTY_SIZE)
             {
                 s32 monToSwitchId = gAiLogicData->mostSuitableMonId[battler];
@@ -1397,6 +1398,7 @@ void AI_TrySwitchOrUseItem(u32 battler)
         }
         else if (ShouldUseItem(battler))
         {
+            SetAIUsingGimmick(battler, NO_GIMMICK);
             return;
         }
     }
diff --git a/src/battle_controller_opponent.c b/src/battle_controller_opponent.c
index e7477f9542..a2d40bc5e1 100644
--- a/src/battle_controller_opponent.c
+++ b/src/battle_controller_opponent.c
@@ -462,12 +462,15 @@ static void OpponentHandleChooseMove(u32 battler)
                     gBattlerTarget = GetBattlerAtPosition(B_POSITION_PLAYER_RIGHT);
             }
             // If opponent can and should use a gimmick (considering trainer data), do it
-            if (gBattleStruct->gimmick.usableGimmick[battler] != GIMMICK_NONE && IsAIUsingGimmick(battler))
+            enum Gimmick usableGimmick = gBattleStruct->gimmick.usableGimmick[battler];
+            if (usableGimmick != GIMMICK_NONE && IsAIUsingGimmick(battler) && !HasTrainerUsedGimmick(battler, usableGimmick))
             {
+                gBattleStruct->gimmick.toActivate |= 1u << battler;
                 BtlController_EmitTwoReturnValues(battler, B_COMM_TO_ENGINE, B_ACTION_EXEC_SCRIPT, (chosenMoveIndex) | (RET_GIMMICK) | (gBattlerTarget << 8));
             }
             else
             {
+                SetAIUsingGimmick(battler, NO_GIMMICK);
                 BtlController_EmitTwoReturnValues(battler, B_COMM_TO_ENGINE, B_ACTION_EXEC_SCRIPT, (chosenMoveIndex) | (gBattlerTarget << 8));
             }
         }
diff --git a/src/battle_controller_player_partner.c b/src/battle_controller_player_partner.c
index 6973dbbc28..37af6497df 100644
--- a/src/battle_controller_player_partner.c
+++ b/src/battle_controller_player_partner.c
@@ -269,12 +269,15 @@ static void PlayerPartnerHandleChooseMove(u32 battler)
             gBattlerTarget = GetBattlerAtPosition(B_POSITION_OPPONENT_RIGHT);
     }
     // If partner can and should use a gimmick (considering trainer data), do it
-    if (gBattleStruct->gimmick.usableGimmick[battler] != GIMMICK_NONE && IsAIUsingGimmick(battler))
+    enum Gimmick usableGimmick = gBattleStruct->gimmick.usableGimmick[battler];
+    if (usableGimmick != GIMMICK_NONE && IsAIUsingGimmick(battler) && !HasTrainerUsedGimmick(battler, usableGimmick))
     {
+        gBattleStruct->gimmick.toActivate |= 1u << battler;
         BtlController_EmitTwoReturnValues(battler, B_COMM_TO_ENGINE, B_ACTION_EXEC_SCRIPT, (chosenMoveIndex) | (RET_GIMMICK) | (gBattlerTarget << 8));
     }
     else
     {
+        SetAIUsingGimmick(battler, NO_GIMMICK);
         BtlController_EmitTwoReturnValues(battler, B_COMM_TO_ENGINE, B_ACTION_EXEC_SCRIPT, (chosenMoveIndex) | (gBattlerTarget << 8));
     }
 
diff --git a/src/battle_gimmick.c b/src/battle_gimmick.c
index 38d60d4365..3969932faf 100644
--- a/src/battle_gimmick.c
+++ b/src/battle_gimmick.c
@@ -91,20 +91,15 @@ bool32 ShouldTrainerBattlerUseGimmick(u32 battler, enum Gimmick gimmick)
 // Returns whether a trainer has used a gimmick during a battle.
 bool32 HasTrainerUsedGimmick(u32 battler, enum Gimmick gimmick)
 {
-    // Check whether partner battler has used gimmick or plans to during turn.
-    if (IsDoubleBattle()
-        && IsPartnerMonFromSameTrainer(battler)
-        && (gBattleStruct->gimmick.activated[BATTLE_PARTNER(battler)][gimmick]
-        || ((gBattleStruct->gimmick.toActivate & (1u << BATTLE_PARTNER(battler))
-        && gBattleStruct->gimmick.usableGimmick[BATTLE_PARTNER(battler)] == gimmick))))
+    if (IsDoubleBattle() && IsPartnerMonFromSameTrainer(battler))
     {
-        return TRUE;
-    }
-    // Otherwise, return whether current battler has used gimmick.
-    else
-    {
-        return gBattleStruct->gimmick.activated[battler][gimmick];
+        u32 partner = BATTLE_PARTNER(battler);
+        if (gBattleStruct->gimmick.activated[partner][gimmick]
+         || ((gBattleStruct->gimmick.toActivate & (1u << partner)) && gBattleStruct->gimmick.usableGimmick[partner] == gimmick))
+            return TRUE;
     }
+
+    return gBattleStruct->gimmick.activated[battler][gimmick];
 }
 
 // Sets a gimmick as used by a trainer with checks for Multi Battles.
diff --git a/src/battle_util.c b/src/battle_util.c
index 95514cd82a..68e89fc93b 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -8938,14 +8938,10 @@ s32 GetStealthHazardDamage(enum TypeSideHazard hazardType, u32 battler)
 
 bool32 IsPartnerMonFromSameTrainer(u32 battler)
 {
-    if (!IsOnPlayerSide(battler) && gBattleTypeFlags & BATTLE_TYPE_TWO_OPPONENTS)
-        return FALSE;
-    else if (IsOnPlayerSide(battler) && gBattleTypeFlags & BATTLE_TYPE_INGAME_PARTNER)
-        return FALSE;
-    else if (gBattleTypeFlags & BATTLE_TYPE_MULTI)
-        return FALSE;
+    if (!IsOnPlayerSide(battler))
+        return !(gBattleTypeFlags & BATTLE_TYPE_TWO_OPPONENTS);
     else
-        return TRUE;
+        return !(gBattleTypeFlags & BATTLE_TYPE_MULTI);
 }
 
 bool32 DoesSpeciesUseHoldItemToChangeForm(u16 species, u16 heldItemId)
diff --git a/test/battle/ai/gimmick_dynamax.c b/test/battle/ai/gimmick_dynamax.c
index 7e99a883c4..99e6157c94 100644
--- a/test/battle/ai/gimmick_dynamax.c
+++ b/test/battle/ai/gimmick_dynamax.c
@@ -37,5 +37,29 @@ AI_SINGLE_BATTLE_TEST("AI uses Dynamax -- AI does not dynamax before using a uti
     }
 }
 
+AI_TWO_VS_ONE_BATTLE_TEST("AI only Dynamaxes once per trainer in 2v1 multi battles")
+{
+    GIVEN {
+        AI_FLAGS(AI_FLAG_CHECK_BAD_MOVE | AI_FLAG_CHECK_VIABILITY | AI_FLAG_TRY_TO_FAINT | AI_FLAG_OMNISCIENT);
+        MULTI_PLAYER(SPECIES_WOBBUFFET) { Moves(MOVE_SPLASH); }
+        MULTI_PARTNER(SPECIES_WOBBUFFET) { Moves(MOVE_SPLASH); }
+        MULTI_OPPONENT_A(SPECIES_WOBBUFFET) { Moves(MOVE_SPLASH); DynamaxLevel(10); }
+        MULTI_OPPONENT_A(SPECIES_WOBBUFFET) { Moves(MOVE_SPLASH); DynamaxLevel(10); }
+    } WHEN {
+        TURN {
+            MOVE(playerLeft, MOVE_SPLASH);
+            MOVE(playerRight, MOVE_SPLASH);
+            EXPECT_MOVE(opponentLeft, MOVE_SPLASH, gimmick: GIMMICK_DYNAMAX);
+            EXPECT_MOVE(opponentRight, MOVE_SPLASH, gimmick: GIMMICK_NONE);
+        }
+        TURN {
+            MOVE(playerLeft, MOVE_SPLASH);
+            MOVE(playerRight, MOVE_SPLASH);
+            EXPECT_MOVE(opponentLeft, MOVE_SPLASH, gimmick: GIMMICK_NONE);
+            EXPECT_MOVE(opponentRight, MOVE_SPLASH, gimmick: GIMMICK_NONE);
+        }
+    }
+}
+
 // Copycatting an ally's Max Guard rendition of Trick Room was a notable strategy.
 TO_DO_BATTLE_TEST("TODO: AI uses Dynamax -- AI uses Copycat against a Dynamaxed Pokemon intelligently")