diff --git a/environment.yml b/environment.yml
index d17f63b5..90164d34 100644
--- a/environment.yml
+++ b/environment.yml
@@ -13,6 +13,7 @@ dependencies:
   - pytest-runner
   - pip
   - pandas
+  - scipy=1.11
   - zeo
   - zodb
   - pip:
diff --git a/pyproject.toml b/pyproject.toml
index c0833017..f4d196ad 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -24,6 +24,7 @@ dependencies = [
     "ctapipe~=0.19",
     "ctapipe-io-nectarcam",
     "pandas",
+    "scipy==1.11",
     "zodb",
     "zeo",
 ]