diff --git a/Makefile b/Makefile
index d057cbbf..31556bc2 100644
--- a/Makefile
+++ b/Makefile
@@ -680,6 +680,8 @@ endif
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=arduino             examples/blinky1
 	@$(MD5SUM) test.hex
+	$(TINYGO) build -size short -o test.hex -target=arduino-leonardo    examples/blinky1
+	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=arduino             examples/pwm
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=arduino -scheduler=tasks  examples/blinky1
diff --git a/src/machine/board_arduino_leonardo.go b/src/machine/board_arduino_leonardo.go
new file mode 100644
index 00000000..01f9570b
--- /dev/null
+++ b/src/machine/board_arduino_leonardo.go
@@ -0,0 +1,39 @@
+//go:build arduino_leonardo
+
+package machine
+
+// Return the current CPU frequency in hertz.
+func CPUFrequency() uint32 {
+	return 16000000
+}
+
+// Digital pins, marked as plain numbers on the board.
+const (
+	D0  = PD2 // RX
+	D1  = PD3 // TX
+	D2  = PD1
+	D3  = PD0
+	D4  = PD4
+	D5  = PC6
+	D6  = PD7
+	D7  = PE6
+	D8  = PB4
+	D9  = PB5
+	D10 = PB6
+	D11 = PB7
+	D12 = PD6
+	D13 = PC7
+)
+
+// LED on the Arduino
+const LED Pin = D13
+
+// ADC on the Arduino
+const (
+	ADC0 Pin = PF7
+	ADC1 Pin = PF6
+	ADC2 Pin = PF5
+	ADC3 Pin = PF4
+	ADC4 Pin = PF1
+	ADC5 Pin = PF0
+)
diff --git a/src/machine/machine_atmega32u4.go b/src/machine/machine_atmega32u4.go
new file mode 100644
index 00000000..8b3faabb
--- /dev/null
+++ b/src/machine/machine_atmega32u4.go
@@ -0,0 +1,76 @@
+//go:build avr && atmega32u4
+
+package machine
+
+import (
+	"device/avr"
+	"runtime/volatile"
+)
+
+const (
+	// Note: start at port B because there is no port A.
+	portB Pin = iota * 8
+	portC
+	portD
+	portE
+	portF
+)
+
+const (
+	PB0 = portB + 0
+	PB1 = portB + 1 // peripherals: Timer1 channel A
+	PB2 = portB + 2 // peripherals: Timer1 channel B
+	PB3 = portB + 3 // peripherals: Timer2 channel A
+	PB4 = portB + 4
+	PB5 = portB + 5
+	PB6 = portB + 6
+	PB7 = portB + 7
+	PC0 = portC + 0
+	PC1 = portC + 1
+	PC2 = portC + 2
+	PC3 = portC + 3
+	PC4 = portC + 4
+	PC5 = portC + 5
+	PC6 = portC + 6
+	PC7 = portC + 7
+	PD0 = portD + 0
+	PD1 = portD + 1
+	PD2 = portD + 2
+	PD3 = portD + 3
+	PD4 = portD + 4
+	PD5 = portD + 5
+	PD6 = portD + 6
+	PD7 = portD + 7
+	PE0 = portE + 0
+	PE1 = portE + 1
+	PE2 = portE + 2
+	PE3 = portE + 3
+	PE4 = portE + 4
+	PE5 = portE + 5
+	PE6 = portE + 6
+	PE7 = portE + 7
+	PF0 = portF + 0
+	PF1 = portF + 1
+	PF2 = portF + 2
+	PF3 = portF + 3
+	PF4 = portF + 4
+	PF5 = portF + 5
+	PF6 = portF + 6
+	PF7 = portF + 7
+)
+
+// getPortMask returns the PORTx register and mask for the pin.
+func (p Pin) getPortMask() (*volatile.Register8, uint8) {
+	switch {
+	case p >= PB0 && p <= PB7: // port B
+		return avr.PORTB, 1 << uint8(p-portB)
+	case p >= PC0 && p <= PC7: // port C
+		return avr.PORTC, 1 << uint8(p-portC)
+	case p >= PD0 && p <= PD7: // port D
+		return avr.PORTD, 1 << uint8(p-portD)
+	case p >= PE0 && p <= PE7: // port E
+		return avr.PORTE, 1 << uint8(p-portE)
+	default: // port F
+		return avr.PORTF, 1 << uint8(p-portF)
+	}
+}
diff --git a/src/runtime/runtime_atmega.go b/src/runtime/runtime_atmega.go
index b2e02445..af547545 100644
--- a/src/runtime/runtime_atmega.go
+++ b/src/runtime/runtime_atmega.go
@@ -1,4 +1,4 @@
-//go:build avr && atmega
+//go:build avr && (atmega || atmega32u4)
 
 package runtime
 
diff --git a/targets/arduino-leonardo.json b/targets/arduino-leonardo.json
new file mode 100644
index 00000000..17652d85
--- /dev/null
+++ b/targets/arduino-leonardo.json
@@ -0,0 +1,10 @@
+{
+	"inherits": ["atmega32u4"],
+	"build-tags": ["arduino_leonardo"],
+	"ldflags": [
+		"--defsym=_bootloader_size=512",
+		"--defsym=_stack_size=512"
+	],
+	"flash-command": "avrdude -c avr109 -p atmega32u4 -b 57600 -P {port} -U flash:w:{hex}:i",
+	"emulator": "simavr -m atmega32u4 -f 16000000 {}"
+}
diff --git a/targets/atmega32u4.json b/targets/atmega32u4.json
new file mode 100644
index 00000000..7aa2c08b
--- /dev/null
+++ b/targets/atmega32u4.json
@@ -0,0 +1,11 @@
+{
+	"inherits": ["avr"],
+	"cpu": "atmega32u4",
+	"build-tags": ["atmega32u4", "avr5"],
+	"serial": "none",
+	"linkerscript": "src/device/avr/atmega32u4.ld",
+	"extra-files": [
+		"targets/avr.S",
+		"src/device/avr/atmega32u4.s"
+	]
+}