diff --git a/data/battle_scripts_1.s b/data/battle_scripts_1.s
index 9d75ac304e..f1eeeccdc9 100644
--- a/data/battle_scripts_1.s
+++ b/data/battle_scripts_1.s
@@ -6843,7 +6843,7 @@ BattleScript_PowderMoveNoEffectWaitMsg:
 BattleScript_MoveUsedFlinched::
 	printstring STRINGID_PKMNFLINCHED
 	waitmessage B_WAIT_TIME_LONG
-	waitmessage B_WAIT_TIME_LONG
+	jumpifability BS_ATTACKER, ABILITY_STEADFAST, BattleScript_TryActivateSteadFast
 BattleScript_MoveUsedFlinchedEnd:
 	goto BattleScript_MoveEnd
 BattleScript_TryActivateSteadFast:
@@ -6853,7 +6853,7 @@ BattleScript_TryActivateSteadFast:
 	copybyte gBattlerAbility, gBattlerAttacker
 	call BattleScript_AbilityPopUp
 	statbuffchange BS_ATTACKER, STAT_CHANGE_ALLOW_PTR, BattleScript_MoveUsedFlinchedEnd
-	setbyte gBattleCommunication STAT_SPEED
+	setbyte gBattleCommunication, STAT_SPEED
 	stattextbuffer
 	printstring STRINGID_ATTACKERABILITYSTATRAISE
 	waitmessage B_WAIT_TIME_LONG
diff --git a/test/battle/ability/steadfast.c b/test/battle/ability/steadfast.c
index fc35e94278..2d6fb5d901 100644
--- a/test/battle/ability/steadfast.c
+++ b/test/battle/ability/steadfast.c
@@ -1,4 +1,56 @@
 #include "global.h"
 #include "test/battle.h"
 
+SINGLE_BATTLE_TEST("Steadfast boosts Speed when the user attempts to move but is flinched")
+{
+    GIVEN {
+        ASSUME(MoveHasAdditionalEffectWithChance(MOVE_FAKE_OUT, MOVE_EFFECT_FLINCH, 100));
+        PLAYER(SPECIES_LUCARIO) { Ability(ABILITY_STEADFAST); }
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(opponent, MOVE_FAKE_OUT); MOVE(player, MOVE_CELEBRATE); }
+    } SCENE {
+        ABILITY_POPUP(player, ABILITY_STEADFAST);
+        NOT ANIMATION(ANIM_TYPE_MOVE, MOVE_CELEBRATE, player);
+    } THEN {
+        EXPECT_EQ(player->statStages[STAT_SPEED], DEFAULT_STAT_STAGE + 1);
+    }
+}
+
+SINGLE_BATTLE_TEST("Steadfast doesn't activate if the user wasn't flinched")
+{
+    GIVEN {
+        ASSUME(MoveHasAdditionalEffectWithChance(MOVE_FAKE_OUT, MOVE_EFFECT_FLINCH, 100));
+        ASSUME(GetItemHoldEffect(ITEM_COVERT_CLOAK) == HOLD_EFFECT_COVERT_CLOAK);
+        PLAYER(SPECIES_LUCARIO) { Ability(ABILITY_STEADFAST); Item(ITEM_COVERT_CLOAK); }
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(opponent, MOVE_FAKE_OUT); MOVE(player, MOVE_CELEBRATE); }
+    } SCENE {
+        NOT ABILITY_POPUP(player, ABILITY_STEADFAST);
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_CELEBRATE, player);
+    } THEN {
+        EXPECT_EQ(player->statStages[STAT_SPEED], DEFAULT_STAT_STAGE);
+    }
+}
+
+DOUBLE_BATTLE_TEST("Steadfast doesn't activate if the user has already moved")
+{
+    GIVEN {
+        ASSUME(MoveHasAdditionalEffect(MOVE_BITE, MOVE_EFFECT_FLINCH));
+        ASSUME(GetMoveEffect(MOVE_INSTRUCT) == EFFECT_INSTRUCT);
+        PLAYER(SPECIES_LUCARIO) { Ability(ABILITY_STEADFAST); }
+        PLAYER(SPECIES_WOBBUFFET);
+        OPPONENT(SPECIES_WOBBUFFET);
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(playerLeft, MOVE_SWORDS_DANCE); MOVE(opponentLeft, MOVE_BITE, target: playerLeft); MOVE(playerRight, MOVE_INSTRUCT, target: playerLeft); }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_SWORDS_DANCE, playerLeft);
+        NOT ABILITY_POPUP(playerLeft, ABILITY_STEADFAST);
+    } THEN {
+        EXPECT_EQ(playerLeft->statStages[STAT_SPEED], DEFAULT_STAT_STAGE);
+    }
+}
+
 TO_DO_BATTLE_TEST("TODO: Write Steadfast (Ability) test titles")