diff --git a/.gitmodules b/.gitmodules
index 1d923356..6441675f 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -989,3 +989,6 @@
 [submodule "libraries/drivers/ft5336"]
 	path = libraries/drivers/ft5336
 	url = https://github.com/adafruit/Adafruit_CircuitPython_FT5336.git
+[submodule "libraries/drivers/mcp3421"]
+	path = libraries/drivers/mcp3421
+	url = https://github.com/adafruit/Adafruit_CircuitPython_MCP3421.git
diff --git a/docs/drivers.rst b/docs/drivers.rst
index 0a8c737c..e862c208 100644
--- a/docs/drivers.rst
+++ b/docs/drivers.rst
@@ -498,6 +498,7 @@ These provide functionality similar to ``analogio``, ``digitalio``, ``pulseio``,
     MCP2515 CAN bus controller <https://docs.circuitpython.org/projects/mcp2515/en/latest/>
     MCP230xx GPIO Expander <https://docs.circuitpython.org/projects/mcp230xx/en/latest/>
     MCP3xxx SPI ADC <https://docs.circuitpython.org/projects/mcp3xxx/en/latest/>
+    MCP3421 18-bit ADC <https://docs.circuitpython.org/projects/mcp3421/en/latest/>
     MCP4725 Digital-to-Analog Converter <https://docs.circuitpython.org/projects/mcp4725/en/latest/>
     MCP4728 4-Channel, 12-bit Digital-to-Analog Converter <https://docs.circuitpython.org/projects/mcp4728/en/latest/>
     MPR121 Capacitive Touch Sensor <https://docs.circuitpython.org/projects/mpr121/en/latest/>
diff --git a/libraries/drivers/mcp3421 b/libraries/drivers/mcp3421
new file mode 160000
index 00000000..975d1af0
--- /dev/null
+++ b/libraries/drivers/mcp3421
@@ -0,0 +1 @@
+Subproject commit 975d1af03f4a5d95fed56a845576097dc7c7328d