diff --git a/stdnum/mz/__init__.py b/stdnum/mz/__init__.py
new file mode 100644
index 00000000..9a98d930
--- /dev/null
+++ b/stdnum/mz/__init__.py
@@ -0,0 +1,24 @@
+# __init__.py - collection of Mozambique numbers
+# coding: utf-8
+#
+# Copyright (C) 2023 Leandro Regueiro
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301 USA
+
+"""Collection of Mozambique numbers."""
+
+# provide aliases
+from stdnum.mz import nuit as vat  # noqa: F401
diff --git a/stdnum/mz/nuit.py b/stdnum/mz/nuit.py
new file mode 100644
index 00000000..3674d17f
--- /dev/null
+++ b/stdnum/mz/nuit.py
@@ -0,0 +1,84 @@
+# nuit.py - functions for handling Mozambique NUIT numbers
+# coding: utf-8
+#
+# Copyright (C) 2023 Leandro Regueiro
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301 USA
+
+"""NUIT (Número Único de Identificação Tributaria, Mozambique tax number).
+
+This number consists of 9 digits, sometimes separated in three groups of three
+digits using whitespace to make it easier to read.
+
+The first digit indicates the type of entity. The next seven digits are a
+sequential number. The last digit is the check digit, which is used to verify
+the number was correctly typed.
+
+More information:
+
+* https://www.mobilize.org.mz/nuit-numero-unico-de-identificacao-tributaria/
+* http://www.at.gov.mz/por/Perguntas-Frequentes2/NUIT
+
+>>> validate('400339910')
+'400339910'
+>>> validate('400 005 834')
+'400005834'
+>>> validate('12345')
+Traceback (most recent call last):
+    ...
+InvalidLength: ...
+>>> format('400339910')
+'400 339 910'
+"""
+
+from stdnum.exceptions import *
+from stdnum.util import clean, isdigits
+
+
+def compact(number):
+    """Convert the number to the minimal representation.
+
+    This strips the number of any valid separators and removes surrounding
+    whitespace.
+    """
+    return clean(number, ' -.').strip()
+
+
+def validate(number):
+    """Check if the number is a valid Mozambique NUIT number.
+
+    This checks the length and formatting.
+    """
+    number = compact(number)
+    if len(number) != 9:
+        raise InvalidLength()
+    if not isdigits(number):
+        raise InvalidFormat()
+    return number
+
+
+def is_valid(number):
+    """Check if the number is a valid Mozambique NUIT number."""
+    try:
+        return bool(validate(number))
+    except ValidationError:
+        return False
+
+
+def format(number):
+    """Reformat the number to the standard presentation format."""
+    number = compact(number)
+    return '-'.join([number[:3], number[3:-3], number[-3:]])
diff --git a/tests/test_mz_nuit.doctest b/tests/test_mz_nuit.doctest
new file mode 100644
index 00000000..80586ea6
--- /dev/null
+++ b/tests/test_mz_nuit.doctest
@@ -0,0 +1,143 @@
+test_mz_nuit.doctest - more detailed doctests for stdnum.mz.nuit module
+
+Copyright (C) 2023 Leandro Regueiro
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA
+
+
+This file contains more detailed doctests for the stdnum.mz.nuit module. It
+tries to test more corner cases and detailed functionality that is not really
+useful as module documentation.
+
+>>> from stdnum.mz import nuit
+
+
+Tests for some corner cases.
+
+>>> nuit.validate('400339910')
+'400339910'
+>>> nuit.validate('400 005 834')
+'400005834'
+>>> nuit.validate('100.033.593')
+'100033593'
+>>> nuit.validate('12345')
+Traceback (most recent call last):
+    ...
+InvalidLength: ...
+>>> nuit.validate('VV3456789')
+Traceback (most recent call last):
+    ...
+InvalidFormat: ...
+>>> nuit.format('400339910')
+'400 339 910'
+>>> nuit.format('100.033.593')
+'100 033 593'
+
+
+These have been found online and should all be valid numbers.
+
+>>> numbers = '''
+...
+... 400339910
+... 400 005 834
+... 500171650
+... 700152855
+... 400 005 834
+... 400027145
+... 400001391
+... 400584291
+... 103017602
+... 101935626
+... 400872120
+... 500001615
+... 400786704
+... 500 024 240
+... 400066183
+... 500006005
+... 401 191 607
+... 400 102 961
+... 105564724
+... 500003545
+... 400787451
+... 116773767
+... 111878641
+... 154695168
+... 102889010
+... 101908372
+... 149349324
+... 400339910
+... 400509182
+... 400 006 245
+... 400778922
+... 400015546
+... 401343261
+... 401120807
+... 400 108 791
+... 400 415 870
+... 108 755 423
+... 108 755 385
+... 400007225
+... 401508317
+... 400535825
+... 400418810
+... 401129006
+... 400058172
+... 400267839
+... 500017341
+... 700074854
+... 401215298
+... 400786704
+... 400058921
+... 400238685
+... 400005516
+... 500050012
+... 400 052 786
+... 400 111 200
+... 400824037
+... 400 410 151
+... 120883275
+... 100002892
+... 118924045
+... 400157715
+... 400370028
+... 129926945
+... 400364001
+... 101002561
+... 400551847
+... 400 769 052
+... 400 120 323
+... 100.033.593
+... 105032031
+... 401430989
+... 103709776
+... 500171650
+... 400316341
+... 400509182
+... 400021260
+... 400129551
+... 400187398
+... 600000063
+... 400102961
+... 400994579
+... 400905649
+... 500003839
+... 401041877
+... 400 380 972
+... 400068038
+...
+... '''
+>>> [x for x in numbers.splitlines() if x and not nuit.is_valid(x)]
+[]