Mitsubishi 3A9 engine#3A91

{{Infobox automobile engine

| image = Mitsubishi 3A90 1.0 Cleartec Engine Spacestar 2013.JPG

| caption = Mitsubishi 3A90 1.0 Mivec Engine (2013 Spacestar)

| name = Mitsubishi 3A9 engine

| manufacturer = MDC Power

| configuration = Naturally aspirated Straight-3

| production = 2003–present

| block = Aluminum

| head = Aluminum

| fueltype = Unleaded regular gasoline, Gasohol E10, E20

| fuelsystem = Fuel injection

| coolingsystem = Water-cooled

| valvetrain = DOHC 4 valves x cyl. with MIVEC

| displacement = {{cvt|999|cc|L|1|disp=flip}}
{{cvt|1124|cc|L|1|disp=flip}}
{{cvt|1193|cc|L|1|disp=flip}}

| bore = {{cvt|75|mm|2}}

| stroke = {{cvt|75.4|mm|2}}
{{cvt|84.8|mm|2}}
{{cvt|90|mm|2}}

| power = {{cvt|52-57|kW|PS bhp|0}}

| torque = {{cvt|88-100|Nm|lbft|0}}

| compression = 10.5:1

}}

The Mitsubishi 3A9 engine is a range of all-alloy three cylinder engines from Mitsubishi Motors that were jointly developed with 4A9 engine family. They were introduced in the 2003 version of their Mitsubishi Colt supermini, and built by DaimlerChrysler-owned MDC Power in Germany (previously a joint venture).

For engine family characteristics see 4A9 engine family.