diff --git a/company.py b/company.py
index 4d9c602071..241971d704 100644
--- a/company.py
+++ b/company.py
@@ -4,14 +4,11 @@ from trytond.model import ModelSQL, ModelView, fields
 from trytond.pool import Pool
 from trytond.pyson import Eval, If
 from trytond.report import Report
+from trytond.tools import timezone as tz
 from trytond.transaction import Transaction
 from trytond.wizard import Button, StateTransition, StateView, Wizard
 
-try:
-    import pytz
-    TIMEZONES = [(x, x) for x in pytz.common_timezones]
-except ImportError:
-    TIMEZONES = []
+TIMEZONES = [(z, z) for z in tz.available_timezones()]
 TIMEZONES += [(None, '')]
 
 Transaction.cache_keys.update({'company', 'employee'})
diff --git a/ir.py b/ir.py
index 5508981fe7..98a449309d 100644
--- a/ir.py
+++ b/ir.py
@@ -1,13 +1,9 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
-try:
-    import pytz
-except ImportError:
-    pytz = None
-
 from trytond.model import (
     EvalEnvironment, ModelSQL, ModelView, dualmethod, fields)
 from trytond.pool import Pool, PoolMeta
+from trytond.tools import timezone as tz
 from trytond.transaction import Transaction
 
 
@@ -41,8 +37,8 @@ class Date(metaclass=PoolMeta):
         company_id = Transaction().context.get('company')
         if timezone is None and company_id:
             company = Company(company_id)
-            if company.timezone and pytz:
-                timezone = pytz.timezone(company.timezone)
+            if company.timezone:
+                timezone = tz.ZoneInfo(company.timezone)
         return super(Date, cls).today(timezone=timezone)
 
 
diff --git a/setup.py b/setup.py
index ed1273ed51..b25d9a4dad 100755
--- a/setup.py
+++ b/setup.py
@@ -140,9 +140,6 @@ setup(name=name,
     license='GPL-3',
     python_requires='>=3.7',
     install_requires=requires,
-    extras_require={
-        'timezone': ['pytz'],
-        },
     dependency_links=dependency_links,
     zip_safe=False,
     entry_points="""