diff --git a/sphinx_needs/directives/needbar.py b/sphinx_needs/directives/needbar.py
index 4a73042a5..be69f0076 100644
--- a/sphinx_needs/directives/needbar.py
+++ b/sphinx_needs/directives/needbar.py
@@ -10,7 +10,7 @@
 from sphinx_needs.data import SphinxNeedsData
 from sphinx_needs.filter_common import FilterBase, filter_needs, prepare_need_list
 from sphinx_needs.logging import get_logger
-from sphinx_needs.utils import add_doc, get_matplotlib, save_matplotlib_figure
+from sphinx_needs.utils import add_doc, import_matplotlib, save_matplotlib_figure
 
 logger = get_logger(__name__)
 
@@ -74,7 +74,7 @@ def run(self) -> Sequence[nodes.Node]:
             text_color = text_color.strip()
 
         style = self.options.get("style")
-        matplotlib = get_matplotlib()
+        matplotlib = import_matplotlib()
         style = style.strip() if style else (matplotlib.style.use("default") if matplotlib else "default")
 
         legend = "legend" in self.options
@@ -165,7 +165,7 @@ def process_needbar(app: Sphinx, doctree: nodes.document, fromdocname: str, foun
     needs_data = SphinxNeedsData(env)
     needs_config = NeedsSphinxConfig(env.config)
 
-    matplotlib = get_matplotlib()
+    matplotlib = import_matplotlib()
 
     if matplotlib is None and found_nodes and needs_config.include_needs:
         logger.warning(
diff --git a/sphinx_needs/directives/needpie.py b/sphinx_needs/directives/needpie.py
index 1174f355b..00e8b9ee4 100644
--- a/sphinx_needs/directives/needpie.py
+++ b/sphinx_needs/directives/needpie.py
@@ -13,7 +13,7 @@
 from sphinx_needs.utils import (
     add_doc,
     check_and_get_external_filter_func,
-    get_matplotlib,
+    import_matplotlib,
     save_matplotlib_figure,
 )
 
@@ -105,7 +105,7 @@ def process_needpie(app: Sphinx, doctree: nodes.document, fromdocname: str, foun
     needs_data = SphinxNeedsData(env)
     needs_config = NeedsSphinxConfig(env.config)
 
-    matplotlib = get_matplotlib()
+    matplotlib = import_matplotlib()
 
     if matplotlib is None and found_nodes and needs_config.include_needs:
         logger.warning(
diff --git a/sphinx_needs/utils.py b/sphinx_needs/utils.py
index 300d0aac9..7b6c76ed6 100644
--- a/sphinx_needs/utils.py
+++ b/sphinx_needs/utils.py
@@ -3,7 +3,7 @@
 import operator
 import os
 import re
-from functools import reduce, wraps
+from functools import lru_cache, reduce, wraps
 from re import Pattern
 from typing import (
     TYPE_CHECKING,
@@ -384,7 +384,12 @@ def jinja_parse(context: Dict[str, Any], jinja_string: str) -> str:
     return content
 
 
-def get_matplotlib() -> Optional["matplotlib"]:
+@lru_cache()
+def import_matplotlib() -> Optional["matplotlib"]:
+    """Import and return matplotlib, or return None if it cannot be imported.
+
+    Also sets the interactive backend to ``Agg``, if ``DISPLAY`` is not set.
+    """
     try:
         import matplotlib
         import matplotlib.pyplot