diff --git a/pyproject.toml b/pyproject.toml
index 30e4372..f8a851a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -19,6 +19,7 @@ dependencies = [
     "sorcha",
     "astropy",
     "scipy",
+    "synphot"
 ]
 
 # On a mac, install optional dependencies with `pip install '.[dev]'` (include the single quotes)