diff --git a/stdnum/tz/__init__.py b/stdnum/tz/__init__.py
new file mode 100644
index 00000000..c8160234
--- /dev/null
+++ b/stdnum/tz/__init__.py
@@ -0,0 +1,21 @@
+# __init__.py - collection of Tanzania 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 Tanzania numbers."""
diff --git a/stdnum/tz/tin.py b/stdnum/tz/tin.py
new file mode 100644
index 00000000..226f4e97
--- /dev/null
+++ b/stdnum/tz/tin.py
@@ -0,0 +1,73 @@
+# tin.py - functions for handling Tanzania TIN 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
+
+"""TIN (Taxpayer Identification Number, or TIN namba, Tanzania tax number).
+
+This number consists of 9 digits, usually separated into three groups
+using hyphens to make it easier to read, like XXX-XXX-XXX.
+
+>>> validate('121-207-079')
+'121207079'
+>>> validate('12345')
+Traceback (most recent call last):
+    ...
+InvalidLength: ...
+>>> format('121207079')
+'121-207-079'
+"""
+
+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 str(clean(number, u' -–').strip())
+
+
+def validate(number):
+    """Check if the number is a valid Tanzania TIN 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 Tanzania TIN 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_tz_tin.doctest b/tests/test_tz_tin.doctest
new file mode 100644
index 00000000..a2318e00
--- /dev/null
+++ b/tests/test_tz_tin.doctest
@@ -0,0 +1,246 @@
+test_tz_tin.doctest - more detailed doctests for stdnum.tz.tin module
+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
+
+
+This file contains more detailed doctests for the stdnum.tz.tin module. It
+tries to test more corner cases and detailed functionality that is not really
+useful as module documentation.
+
+>>> from stdnum.tz import tin
+
+
+Tests for some corner cases.
+
+>>> tin.validate('121-207-079')
+'121207079'
+>>> tin.validate(u'121–207–079')
+'121207079'
+>>> tin.validate('121 207 079')
+'121207079'
+>>> tin.validate('121 - 207 - 079')
+'121207079'
+>>> tin.validate('121207079')
+'121207079'
+>>> tin.format('121207079')
+'121-207-079'
+>>> tin.validate('12345')
+Traceback (most recent call last):
+    ...
+InvalidLength: ...
+>>> tin.validate('VV3456789')
+Traceback (most recent call last):
+    ...
+InvalidFormat: ...
+
+
+These have been found online and should all be valid numbers.
+
+>>> numbers = u'''
+...
+... 121-207-079
+... 117-030-407
+... 130-393-985
+... 139 457 471
+... 135-000-205
+... 107-618-627
+... 124-753-783
+... 120-662-023
+... 105-038-321
+... 105-669-445
+... 139-384-059
+... 133-604-049
+... 142-303-175
+... 138-506-789
+... 100-849-089
+... 107-211-748
+... 141-076-841
+... 115-793-217
+... 156-158-429
+... 100-168-375
+... 127-321-361
+... 121-899-779
+... 108-711-744
+... 130-376-134
+... 136-449-125
+... 138-921-646
+... 102-158-008
+... 127-975-116
+... 110-496-907
+... 105-437-706
+... 101-325-695
+... 100-784-661
+... 129-210-958
+... 124-530-725
+... 120-332-694
+... 144 - 532 - 074
+... 101-345-467
+... 111-169-268
+... 105-875-304
+... 108-537-108
+... 100-147-181
+... 128-755-586
+... 100-145-804
+... 102-072-286
+... 120-992-864
+... 123-854-233
+... 142-253-011
+... 101-042-197
+... 101-195-651
+... 130 307 337
+... 138-360-679
+... 130-084-273
+... 107-089-765
+... 144-436-253
+... 130-265-529
+... 132760721
+... 135-972-118
+... 105-632-991
+... 101-034-879
+... 112-911-847
+... 100-195-232
+... 120-884-336
+... 110-170-335
+... 100-895-803
+... 129-506-202
+... 145-456-789
+... 120-537-776
+... 136-968-017
+... 100-202-646
+... 103150524
+... 117-953-300
+... 125-181-317
+... 134-267-437
+... 125 319 890
+... 122-452-328
+... 118-847-407
+... 107-855-106
+... 116-738-023
+... 144-372-069
+... 100-146-630
+... 102-825-128
+... 113-521-937
+... 128-263-454
+... 138-675-009
+... 120-364-529
+... 141-610-678
+... 126 – 041 – 349
+... 108-998-350
+... 115-577-239
+... 125-885-020
+... 132-800-723
+... 110-402-910
+... 138-692-302
+... 103-626-137
+... 153-443-971
+... 111-927-480
+... 116-285-088
+... 129-937-084
+... 142-002-078
+... 115-302-302
+... 127-491-690
+... 127- 532-931
+... 103-410-444
+... 101-346-943
+... 154-318-933
+... 139-793-412
+... 100147181
+... 130-210- 392
+... 138-584-666
+... 120-036-815
+... 117-653-218
+... 131-946-961
+... 118-690-265
+... 125-801-153
+... 129-042-877
+... 135-202-827
+... 115-575-503
+... 106-091-625
+... 120-723-987
+... 122-044-483
+... 104-746-047
+... 123-854-233
+... 100-101-297
+... 117-305-341
+... 107-075-259
+... 100-178-117
+... 107-966-013
+... 112-166-386
+... 122-034-178
+... 138-882-756
+... 117-409-171
+... 107-260-692
+... 100-197-898
+... 137-843-951
+... 107-199-101
+... 126-085-451
+... 135-769-827
+... 118-926-862
+... 115-692-127
+... 126-471-688 
+... 112-351-035
+... 123-288-602
+... 121-786-524
+... 113-225-246
+... 138-007-286
+... 122-992-136
+... 101-041-662
+... 139-953-462
+... 109-345-180
+... 908-263-792
+... 111-588-198
+... 125-967-574
+... 107-588-582
+... 116-800-403
+... 101-299-570
+... 139-362-756
+... 131-057-857
+... 106-736-839
+... 101-151-425
+... 101-668-479
+... 104-368-867
+... 113-663-903
+... 121-666-944
+... 135-703-877
+... 132-761-728
+... 106-955-581
+... 130-882-110
+... 105-861-400
+... 140-564-044
+... 134-154-497
+... 115-236-776
+... 129-515-406
+... 119-343-100
+... 110-034-326
+... 119-264-251
+... 101-024-490
+... 107-538-844
+... 101-473-368
+... 104-979-386
+... 100-173-697
+... 106-535-590
+... 140-148-628
+... 111-039-240
+... 105541295
+... 100582775
+... 100254484
+...
+... '''
+>>> [x for x in numbers.splitlines() if x and not tin.is_valid(x)]
+[]