diff --git a/docs/changes.rst b/docs/changes.rst
index 752f9eedb..063957f43 100644
--- a/docs/changes.rst
+++ b/docs/changes.rst
@@ -16,6 +16,8 @@ Pending
   ``debug_toolbar.store.DatabaseStore`` with ``SKIP_TOOLBAR_QUERIES``.
 * Fixed font family for code blocks and stack traces in the toolbar.
 * Added test to confirm Django's ``TestCase.assertNumQueries`` works.
+* Updated tox configuration to treat ``DeprecationWarning``,
+  ``ResourceWarning``, and ``PendingDeprecationWarning`` as errors.
 
 6.1.0 (2025-10-30)
 ------------------
diff --git a/tox.ini b/tox.ini
index e7058e0fd..5223bd56a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -43,7 +43,11 @@ passenv=
     GITHUB_*
 setenv =
     PYTHONPATH = {toxinidir}
-    PYTHONWARNINGS = d
+    PYTHONWARNINGS =\
+        error::ResourceWarning,\
+        error::DeprecationWarning,\
+        error::PendingDeprecationWarning,\
+        ignore:The RedirectsPanel is deprecated:DeprecationWarning
     DB_NAME = {env:DB_NAME:debug_toolbar}
     DB_USER = {env:DB_USER:debug_toolbar}
     DB_HOST = {env:DB_HOST:localhost}
@@ -51,7 +55,7 @@ setenv =
     DJANGO_SETTINGS_MODULE = tests.settings
 allowlist_externals = make
 pip_pre = True
-commands = python -b -W always -m coverage run -m django test -v2 {posargs:tests}
+commands = python -b -m coverage run -m django test -v2 {posargs:tests}
 
 
 [testenv:py{310,311,312,313,314}-dj{42,51,52,60,main}-{postgresql,psycopg3}]