diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index d49f1d7a..ce7135c7 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -38,7 +38,7 @@ repos:
       - id: mypy
         pass_filenames: false
         args: [--package=guppylang]
-        additional_dependencies: [ormsgpack, pydantic]
+        additional_dependencies: [ormsgpack, pydantic, graphviz, networkx]
 
   - repo: local
     hooks:
diff --git a/guppylang/hugr/hugr.py b/guppylang/hugr/hugr.py
index 07db8f1d..9059c3c7 100644
--- a/guppylang/hugr/hugr.py
+++ b/guppylang/hugr/hugr.py
@@ -5,7 +5,7 @@
 from dataclasses import dataclass, field
 from typing import Any, Optional
 
-import networkx as nx  # type: ignore[import-not-found]
+import networkx as nx  # type: ignore[import-untyped]
 
 import guppylang.hugr.ops as ops
 import guppylang.hugr.raw as raw
diff --git a/guppylang/hugr/visualise.py b/guppylang/hugr/visualise.py
index d1428a73..590861ec 100644
--- a/guppylang/hugr/visualise.py
+++ b/guppylang/hugr/visualise.py
@@ -3,7 +3,7 @@
 from collections.abc import Iterable
 from typing import TYPE_CHECKING
 
-import graphviz as gv  # type: ignore[import-not-found]
+import graphviz as gv  # type: ignore[import-untyped]
 
 from guppylang.cfg.analysis import (
     DefAssignmentDomain,