diff --git a/manage.py b/manage.py
index 6161b18..43c74b3 100755
--- a/manage.py
+++ b/manage.py
@@ -5,13 +5,13 @@
 import os
 import re
 import subprocess
+import tomllib
 from collections import Counter, defaultdict
 from operator import itemgetter
 from pathlib import Path
 
 import click
 import requests
-import tomli
 from ocdsextensionregistry import ExtensionRegistry
 
 extensions_url = "https://raw.githubusercontent.com/open-contracting/extension_registry/main/extensions.csv"
@@ -286,7 +286,7 @@ def count_dependencies(directory):
             if pyproject.is_file():
                 counter.update(
                     pattern.split(req)[0]
-                    for req in tomli.loads(pyproject.read_text()).get("project", {}).get("dependencies", [])
+                    for req in tomllib.loads(pyproject.read_text()).get("project", {}).get("dependencies", [])
                 )
 
     for requirement, count in reversed(counter.most_common()):
diff --git a/requirements.in b/requirements.in
index 79f4f7f..70aa82c 100644
--- a/requirements.in
+++ b/requirements.in
@@ -1,4 +1,3 @@
 click
 ocdsextensionregistry
 requests
-tomli
diff --git a/requirements.txt b/requirements.txt
index d63ff3e..1e7f782 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -31,8 +31,6 @@ requests-cache==1.2.1
     # via ocdsextensionregistry
 six==1.16.0
     # via url-normalize
-tomli==2.0.2
-    # via -r requirements.in
 url-normalize==1.4.3
     # via requests-cache
 urllib3==2.8.0
diff --git a/requirements_dev.txt b/requirements_dev.txt
index 034f114..cda2247 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -94,13 +94,13 @@ rpds-py==2026.6.3
     # via
     #   jsonschema
     #   referencing
+setuptools==84.2.1
+    # via -r requirements_dev.in
 six==1.16.0
     # via
     #   -r requirements.txt
     #   rfc3339-validator
     #   url-normalize
-tomli==2.0.2
-    # via -r requirements.txt
 url-normalize==1.4.3
     # via
     #   -r requirements.txt
diff --git a/tests/install.sh b/tests/install.sh
index b7fb25e..172663c 100644
--- a/tests/install.sh
+++ b/tests/install.sh
@@ -3,7 +3,7 @@
 set -eu
 
 pip install ruff 'jscc>=0.5.0' json-merge-patch jsonref jsonschema ocdsextensionregistry ocdskit packaging pytest \
-    requests rfc3339-validator rfc3986-validator setuptools tomli # Python 3.10 or less
+    requests rfc3339-validator rfc3986-validator setuptools
 
 curl -s -S --retry 3 -o /tmp/test_csv.py "$BASEDIR"/tests/test_csv.py
 curl -s -S --retry 3 -o /tmp/test_json.py "$BASEDIR"/tests/test_json.py
diff --git a/tests/script.sh b/tests/script.sh
index 5b74cbd..0da2d09 100644
--- a/tests/script.sh
+++ b/tests/script.sh
@@ -227,11 +227,6 @@ if [ -d docs ]; then
         "'copyright'"
     )
 fi
-if [ ! -f .python-version ] || grep 3.10 .python-version > /dev/null; then
-    IGNORE+=(
-        PYI024 # collections-named-tuple (Python 3.11+)
-    )
-fi
 if [ -f MANIFEST.in ]; then
     PER_FILE_IGNORES+=(
         tests/*:ARG001 # unused-function-argument (fixtures)
diff --git a/tests/test_requirements.py b/tests/test_requirements.py
index 00de81e..8469077 100644
--- a/tests/test_requirements.py
+++ b/tests/test_requirements.py
@@ -1,6 +1,7 @@
 import ast
 import glob
 import os
+import tomllib
 from collections import defaultdict
 from importlib.metadata import distribution
 from pathlib import Path
@@ -10,15 +11,6 @@
 from packaging.requirements import Requirement
 from setuptools import find_packages
 
-try:
-    import tomllib
-
-    TOMLLIB_STDLIB = True
-except ImportError:
-    import tomli as tomllib  # Python 3.10 or less
-
-    TOMLLIB_STDLIB = False
-
 path = os.getcwd()
 
 # https://github.com/PyCQA/isort/blob/develop/isort/stdlibs/py39.py
@@ -209,6 +201,7 @@
     "tkinter",
     "token",
     "tokenize",
+    "tomllib",
     "trace",
     "traceback",
     "tracemalloc",
@@ -239,8 +232,6 @@
     "zlib",
     "zoneinfo",
 }
-if TOMLLIB_STDLIB:
-    stdlib.add("tomllib")
 
 
 IGNORE = [