diff --git a/CHANGES b/CHANGES
index a597206d0..4e5f36c7b 100644
--- a/CHANGES
+++ b/CHANGES
@@ -45,6 +45,7 @@ Misc:
  - Core: Add SHA1 hashing for ROMs
  - FFmpeg: Add Ut Video option
  - GB: Prevent incompatible BIOSes from being used on differing models
+ - GB MBC: Add M161 support for one Mani 4-in-1 multicart
  - GB Serialize: Add missing savestate support for MBC6 and NT (newer)
  - GBA: Improve detection of valid ELF ROMs
  - GBA Audio: Remove broken XQ audio pending rewrite
diff --git a/README.md b/README.md
index 5bb847e9f..78b49cf7f 100644
--- a/README.md
+++ b/README.md
@@ -54,6 +54,7 @@ The following mappers are fully supported:
 - MBC5
 - MBC5+Rumble
 - MBC7
+- M161
 - Wisdom Tree (unlicensed)
 - NT "old type" 1 and 2 (unlicensed multicart)
 - NT "new type" (unlicensed MBC5-like)
diff --git a/include/mgba/gb/interface.h b/include/mgba/gb/interface.h
index e9bec3044..f32c25773 100644
--- a/include/mgba/gb/interface.h
+++ b/include/mgba/gb/interface.h
@@ -37,6 +37,7 @@ enum GBMemoryBankControllerType {
 	GB_HuC3 = 0x12,
 	GB_POCKETCAM = 0x13,
 	GB_TAMA5 = 0x14,
+	GB_M161 = 0x15,
 	GB_MBC3_RTC = 0x103,
 	GB_MBC5_RUMBLE = 0x105,
 	GB_UNL_WISDOM_TREE = 0x200,
diff --git a/include/mgba/internal/gb/memory.h b/include/mgba/internal/gb/memory.h
index 2d1278feb..9bee51724 100644
--- a/include/mgba/internal/gb/memory.h
+++ b/include/mgba/internal/gb/memory.h
@@ -233,6 +233,11 @@ struct GBHuC3State {
 	uint8_t registers[256];
 };
 
+struct GBM161State {
+	bool locked;
+	uint8_t bank;
+};
+
 struct GBPKJDState {
 	uint8_t reg[2];
 };
@@ -276,6 +281,7 @@ union GBMBCState {
 	struct GBPocketCamState pocketCam;
 	struct GBTAMA5State tama5;
 	struct GBHuC3State huc3;
+	struct GBM161State m161;
 	struct GBNTOldState ntOld;
 	struct GBNTNewState ntNew;
 	struct GBPKJDState pkjd;
diff --git a/include/mgba/internal/gb/serialize.h b/include/mgba/internal/gb/serialize.h
index 4963340e5..72fe9c436 100644
--- a/include/mgba/internal/gb/serialize.h
+++ b/include/mgba/internal/gb/serialize.h
@@ -432,6 +432,10 @@ struct GBSerializedState {
 				uint8_t value;
 				uint8_t mode;
 			} huc3;
+			struct {
+				uint8_t bank;
+				uint8_t locked;
+			} m161;
 			struct {
 				GBSerializedNTOldFlags flags;
 				uint8_t baseBank;
diff --git a/src/gb/mbc.c b/src/gb/mbc.c
index 551071548..c6f7b9183 100644
--- a/src/gb/mbc.c
+++ b/src/gb/mbc.c
@@ -110,7 +110,7 @@ static struct {
 	{"HUC1", GB_HuC1},
 	{"HUC3", GB_HuC3},
 	{"TAM5", GB_TAMA5},
-	{"M161", GB_MBC_AUTODETECT}, // TODO
+	{"M161", GB_M161},
 	{"BBD", GB_UNL_BBD},
 	{"HITK", GB_UNL_HITEK},
 	{"SNTX", GB_UNL_SINTAX},
@@ -460,6 +460,9 @@ void GBMBCInit(struct GB* gb) {
 			gb->memory.cam->startRequestImage(gb->memory.cam, GBCAM_WIDTH, GBCAM_HEIGHT, mCOLOR_ANY);
 		}
 		break;
+	case GB_M161:
+		gb->memory.mbcWrite = _GBM161;
+		break;
 	case GB_UNL_WISDOM_TREE:
 		gb->memory.mbcWrite = _GBWisdomTree;
 		break;
diff --git a/src/gb/mbc/mbc-private.h b/src/gb/mbc/mbc-private.h
index b6f7671a5..9b6e11b89 100644
--- a/src/gb/mbc/mbc-private.h
+++ b/src/gb/mbc/mbc-private.h
@@ -24,6 +24,7 @@ void _GBMBC7(struct GB*, uint16_t address, uint8_t value);
 void _GBMMM01(struct GB*, uint16_t address, uint8_t value);
 void _GBPocketCam(struct GB* gb, uint16_t address, uint8_t value);
 void _GBTAMA5(struct GB* gb, uint16_t address, uint8_t value);
+void _GBM161(struct GB* gb, uint16_t address, uint8_t value);
 
 void _GBHuC1(struct GB*, uint16_t address, uint8_t value);
 void _GBHuC3(struct GB*, uint16_t address, uint8_t value);
diff --git a/src/gb/mbc/mbc.c b/src/gb/mbc/mbc.c
index 699bdb209..59ab4af5b 100644
--- a/src/gb/mbc/mbc.c
+++ b/src/gb/mbc/mbc.c
@@ -565,3 +565,19 @@ void _GBMBC7Write(struct GBMemory* memory, uint16_t address, uint8_t value) {
 	}
 	mbc7->eeprom = value;
 }
+
+void _GBM161(struct GB* gb, uint16_t address, uint8_t value) {
+	UNUSED(address);
+
+	struct GBM161State* m161 = &gb->memory.mbcState.m161;
+	if (m161->locked) {
+		return;
+	}
+
+	int bank = value & 0x7;
+	m161->bank = bank;
+	m161->locked = true;
+
+	GBMBCSwitchBank0(gb, bank * 2);
+	GBMBCSwitchBank(gb, bank * 2 + 1);
+}
diff --git a/src/gb/memory.c b/src/gb/memory.c
index f2bfa17a4..e6544c27d 100644
--- a/src/gb/memory.c
+++ b/src/gb/memory.c
@@ -840,6 +840,10 @@ void GBMemorySerialize(const struct GB* gb, struct GBSerializedState* state) {
 		state->memory.mmm01.locked = memory->mbcState.mmm01.locked;
 		state->memory.mmm01.bank0 = memory->mbcState.mmm01.currentBank0;
 		break;
+	case GB_M161:
+		state->memory.m161.locked = memory->mbcState.m161.locked;
+		state->memory.m161.bank = memory->mbcState.m161.bank;
+		break;
 	case GB_UNL_NT_OLD_1:
 	case GB_UNL_NT_OLD_2:
 		state->memory.ntOld.flags = GBSerializedNTOldFlagsSetSwapped(0, memory->mbcState.ntOld.swapped);
@@ -1006,6 +1010,12 @@ void GBMemoryDeserialize(struct GB* gb, const struct GBSerializedState* state) {
 			GBMBCSwitchBank0(gb, gb->memory.romSize / GB_SIZE_CART_BANK0 - 2);
 		}
 		break;
+	case GB_M161:
+		memory->mbcState.m161.locked = state->memory.m161.locked;
+		memory->mbcState.m161.bank = state->memory.m161.bank & 0x7;
+		GBMBCSwitchBank0(gb, memory->mbcState.m161.bank * 2);
+		GBMBCSwitchBank(gb, memory->mbcState.m161.bank * 2 + 1);
+		break;
 	case GB_UNL_NT_OLD_1:
 	case GB_UNL_NT_OLD_2:
 		memory->mbcState.ntOld.swapped = GBSerializedNTOldFlagsGetSwapped(state->memory.ntOld.flags);
diff --git a/src/gb/overrides.c b/src/gb/overrides.c
index 20e489b9a..c3799e0c0 100644
--- a/src/gb/overrides.c
+++ b/src/gb/overrides.c
@@ -667,6 +667,8 @@ static const struct GBCartridgeOverride _sgbOverrides[] = {
 };
 
 static const struct GBCartridgeOverride _overrides[] = {
+	{ 0xA61F3EE1, GB_MODEL_AUTODETECT, GB_M161, { 0 } }, // Mani 4 in 1 - Tetris + Alleyway + Yakuman + Tennis
+
 	// Pokemon Spaceworld 1997 demo
 	{ 0x232A067D, GB_MODEL_AUTODETECT, GB_MBC3_RTC, { 0 } }, // Gold (debug)
 	{ 0x630ED957, GB_MODEL_AUTODETECT, GB_MBC3_RTC, { 0 } }, // Gold (non-debug)
diff --git a/src/platform/qt/GameBoy.cpp b/src/platform/qt/GameBoy.cpp
index 8aec1ea13..e6adbcce6 100644
--- a/src/platform/qt/GameBoy.cpp
+++ b/src/platform/qt/GameBoy.cpp
@@ -33,6 +33,7 @@ static const QList<GBMemoryBankControllerType> s_mbcList{
 	GB_TAMA5,
 	GB_HuC1,
 	GB_HuC3,
+	GB_M161,
 	GB_UNL_WISDOM_TREE,
 	GB_UNL_PKJD,
 	GB_UNL_NT_OLD_1,
@@ -92,6 +93,7 @@ QString GameBoy::mbcName(GBMemoryBankControllerType mbc) {
 		s_mbcNames[GB_HuC3] = "HuC-3";
 		s_mbcNames[GB_POCKETCAM] = "Pocket Cam";
 		s_mbcNames[GB_TAMA5] = "TAMA5";
+		s_mbcNames[GB_M161] = "M161";
 		s_mbcNames[GB_UNL_WISDOM_TREE] = "Wisdom Tree";
 		s_mbcNames[GB_UNL_NT_OLD_1] = tr("%1 (old 1)").arg("NT");
 		s_mbcNames[GB_UNL_NT_OLD_2] = tr("%1 (old 2)").arg("NT");