diff --git a/include/pokemon.h b/include/pokemon.h
index 1326e81329..574eafce0e 100644
--- a/include/pokemon.h
+++ b/include/pokemon.h
@@ -809,5 +809,6 @@ u32 CheckDynamicMoveType(struct Pokemon *mon, u32 move, u32 battler);
 uq4_12_t GetDynamaxLevelHPMultiplier(u32 dynamaxLevel, bool32 inverseMultiplier);
 u32 GetRegionalFormByRegion(u32 species, u32 region);
 bool32 IsSpeciesForeignRegionalForm(u32 species, u32 currentRegion);
+u32 GetTeraTypeFromPersonality(struct Pokemon *mon);
 
 #endif // GUARD_POKEMON_H
diff --git a/src/debug.c b/src/debug.c
index 8a20e6b2b1..4443e004d8 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -3416,8 +3416,8 @@ static void DebugAction_Give_Pokemon_ComplexCreateMon(u8 taskId) //https://githu
     SetMonData(&mon, MON_DATA_DYNAMAX_LEVEL, &dmaxLevel);
 
     // tera type
-    if (teraType >= NUMBER_OF_MON_TYPES)
-        teraType = TYPE_NONE;
+    if (teraType == TYPE_NONE || teraType == TYPE_MYSTERY || teraType >= NUMBER_OF_MON_TYPES)
+        teraType = GetTeraTypeFromPersonality(&mon);
     SetMonData(&mon, MON_DATA_TERA_TYPE, &teraType);
 
     //IVs
diff --git a/src/pokemon.c b/src/pokemon.c
index ef90f10ba3..789935c654 100644
--- a/src/pokemon.c
+++ b/src/pokemon.c
@@ -1198,6 +1198,9 @@ void CreateBoxMon(struct BoxPokemon *boxMon, u16 species, u8 level, u8 fixedIV,
     SetBoxMonData(boxMon, MON_DATA_POKEBALL, &value);
     SetBoxMonData(boxMon, MON_DATA_OT_GENDER, &gSaveBlock2Ptr->playerGender);
 
+    u32 teraType = (boxMon->personality & 0x1) == 0 ? gSpeciesInfo[species].types[0] : gSpeciesInfo[species].types[1];
+    SetBoxMonData(boxMon, MON_DATA_TERA_TYPE, &teraType);
+
     if (fixedIV < USE_RANDOM_IVS)
     {
         SetBoxMonData(boxMon, MON_DATA_HP_IV, &fixedIV);
@@ -7063,3 +7066,9 @@ bool32 IsSpeciesForeignRegionalForm(u32 species, u32 currentRegion)
     }
     return FALSE;
 }
+
+u32 GetTeraTypeFromPersonality(struct Pokemon *mon)
+{
+    const u8 *types = gSpeciesInfo[GetMonData(mon, MON_DATA_SPECIES)].types;
+    return (GetMonData(mon, MON_DATA_PERSONALITY) & 0x1) == 0 ? types[0] : types[1];
+}
diff --git a/src/script_pokemon_util.c b/src/script_pokemon_util.c
index 77ce6411db..7288870441 100644
--- a/src/script_pokemon_util.c
+++ b/src/script_pokemon_util.c
@@ -373,8 +373,8 @@ static u32 ScriptGiveMonParameterized(u8 side, u8 slot, u16 species, u8 level, u
     SetMonData(&mon, MON_DATA_DYNAMAX_LEVEL, &dmaxLevel);
 
     // tera type
-    if (teraType >= NUMBER_OF_MON_TYPES)
-        teraType = TYPE_NONE;
+    if (teraType == TYPE_NONE || teraType == TYPE_MYSTERY || teraType >= NUMBER_OF_MON_TYPES)
+        teraType = GetTeraTypeFromPersonality(&mon);
     SetMonData(&mon, MON_DATA_TERA_TYPE, &teraType);
 
     // EV and IV
diff --git a/test/pokemon.c b/test/pokemon.c
index 97e034dc82..16aadee798 100644
--- a/test/pokemon.c
+++ b/test/pokemon.c
@@ -57,6 +57,8 @@ TEST("Terastallization type is reset to the default types when setting Tera Type
     CreateMon(&mon, SPECIES_PIDGEY, 100, 0, FALSE, 0, OT_ID_PRESET, 0);
     SetMonData(&mon, MON_DATA_TERA_TYPE, &teraType);
     EXPECT_EQ(teraType, GetMonData(&mon, MON_DATA_TERA_TYPE));
+    if (typeNone == TYPE_NONE)
+        typeNone = GetTeraTypeFromPersonality(&mon);
     SetMonData(&mon, MON_DATA_TERA_TYPE, &typeNone);
     typeNone = GetMonData(&mon, MON_DATA_TERA_TYPE);
     EXPECT(typeNone == gSpeciesInfo[SPECIES_PIDGEY].types[0]