diff --git a/README.md b/README.md
index 6d453b0..49ae2a0 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,17 @@ To install from source, clone the repo then run:
 pip install .
 ```
 
-## Usage
+To run the GUI, Tk must be installed. For example, on macOS:
+```
+sudo port install py311-tkinter
+sudo port install tk -x11 +quartz
+```
+
+## GUI Usage
+
+The `pydiode-gui` command will launch the user interface.
+
+## Command-Line Usage
 
 Documentation:
 ```
diff --git a/pyproject.toml b/pyproject.toml
index 044fac8..4031ef5 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,3 +23,4 @@ classifiers = [
 
 [project.scripts]
 pydiode = "pydiode.main:main"
+pydiode-gui = "pydiode.gui:main"
diff --git a/gui.py b/src/pydiode/gui.py
similarity index 100%
rename from gui.py
rename to src/pydiode/gui.py