| Tamgo Oy | Transport & logistics | 2025 |
| Tamhockey Oy | Arts & recreation | 1999 |
| Taminfo Oy | Manufacturing | 1987 |
| Tamkate Oy | Construction | 2013 |
| Tamkopio Oy | Administrative & support | 1982 |
| Tamkotek Oy | Professional & scientific | 1989 |
| Tamlog Oy | Professional & scientific | 2010 |
| Tamlynx Oy | Professional & scientific | 2025 |
| Tammed Oy | Wholesale & retail | 1994 |
| Tammek Oy | Manufacturing | 2021 |
| Tammelan Burger Oy | Hospitality | 1997 |
| Tammelan Hovi Oy | Hospitality | 2011 |
| Tammelan Kirkkoahde Oy | Construction | 1989 |
| Tammelan Kukka Ky | Wholesale & retail | 2013 |
| Tammelan Löytö Oy | Wholesale & retail | 2025 |
| Tammelan Talotekniikka Oy | Professional & scientific | 2002 |
| Tammelan Terveyspalvelut Ky | Health & social care | 2002 |
| Tammenlehväkeskus Oy | Health & social care | 2007 |
| Tammentalo Oy | Real estate | 2013 |
| Tammer Apartments Oy | Real estate | 2023 |
| Tammer Art Oy | Wholesale & retail | 2022 |
| Tammer BioLab Oy | Manufacturing | 1987 |
| Tammer Brands Oy | Wholesale & retail | 1954 |
| Tammer Capital Oy | Professional & scientific | 2024 |
| Tammer Diesel Oy | Other services | 1954 |
| Tammer Kodinrakennus Oy | Real estate | 2021 |
| Tammer Talotekniikka Oy | Real estate | 2013 |
| Tammer Urakointi Oy | Construction | 2026 |
| Tammer-Asunnot Oy | Real estate | 2004 |
| Tammer-Data Oy | Wholesale & retail | 2008 |
| Tammer-Isännöinti Oy | Real estate | 1986 |
| Tammer-Kallio Oy | Construction | 2022 |
| Tammer-Kansio Ky | | 1983 |
| Tammer-Kortit Oy | Wholesale & retail | 1978 |
| Tammer-Koski Consulting Ky | Arts & recreation | 2007 |
| Tammer-Laite Oy | Administrative & support | 1996 |
| Tammer-Piano ja Soitin Ky | Wholesale & retail | 1975 |
| Tammer-Pirkka Oy | Real estate | 1988 |
| Tammer-Puhallin Oy | Construction | 1987 |
| Tammer-Rakennus Oy | Construction | 1997 |
| Tammer-Saneeraus Oy | Construction | 2020 |
| Tammer-Tulkit Oy | Administrative & support | 2016 |
| Tammer-Tuote Oy | Manufacturing | 1985 |
| TammerCode Oy | Information & communication | 2018 |
| TammerHousing Oy | Real estate | 2021 |
| Tammerch Finland Oy | Wholesale & retail | 1991 |
| Tammerfocus Oy | Health & social care | 1997 |
| Tammerfors Linne och Jern Ab | Financial services | 1942 |
| Tammerkki Oy | Manufacturing | 1983 |
| Tammerkosken Auto-opisto Oy | Education | 1963 |
| Tammerkosken Kukka ja Hautauspalvelu Ky | Other services | 1992 |
| Tammerkosken Leipä Oy | Manufacturing | 2023 |
| Tammerkosken Ravintolat Oy | Hospitality | 2006 |
| Tammerkosken Takomo Oy | Manufacturing | 1999 |
| Tammerkosken Teollisuus Oy | Manufacturing | 1987 |
| Tammerkosken Titaani Oy | Health & social care | 2019 |
| Tammerkoti LKV Oy | Real estate | 2017 |
| Tammermaan Lähihuolto Oy | Administrative & support | 1992 |
| Tammermaan Tilitoimisto Oy | Professional & scientific | 1985 |
| Tammerneon Oy | Manufacturing | 2005 |
| Tammernet Oy | Financial services | 1998 |
| Tammerparts Oy | Wholesale & retail | 2018 |
| Tammersiivous Ky | Administrative & support | 1984 |
| Tammersoft Oy | Information & communication | 2020 |
| Tammersteel Oy | Wholesale & retail | 2019 |
| Tammertalkkarit Oy | Administrative & support | 2019 |
| Tammervoima Oy | Energy | 2011 |
| Tammilehto Group Oy | Financial services | 2021 |
| Tamminen TaxLaw Ky | Professional & scientific | 2009 |
| Tammisalo Yhtiöt Oy | Construction | 2016 |
| Tamneule Oy | Wholesale & retail | 1992 |
| Tampark Oy | Manufacturing | 2020 |
| TampeRePro Oy | Professional & scientific | 2025 |
| TampeRent Oy | Transport & logistics | 2013 |
| Tampellan Toimistotalo Oy | Real estate | 2017 |
| Tampellan Työhuone Oy | Professional & scientific | 2006 |
| Tampere Areena Oy | Administrative & support | 1996 |
| Tampere Business Center Oy | Real estate | 1991 |
| Tampere Deck and Arena Management Oy | Professional & scientific | 2019 |
| Tampere Diamond Oy | Real estate | 2026 |
| Tampere Dream Hostel Oy | Hospitality | 2009 |
| Tampere Open Oy | Arts & recreation | 2006 |
| Tampere Putiikki Oy | Wholesale & retail | 2024 |
| Tampere Social Dancing Oy | Education | 2023 |
| Tampere Spine Clinic Oy | Health & social care | 2019 |
| Tampere Startup Hub Oy | Administrative & support | 2020 |
| Tampere United jalkapallo Oy | Arts & recreation | 2024 |
| Tampere-talo Oy | Real estate | 1988 |
| TampereMissio Palvelut Oy | Health & social care | 2019 |
| Tampereen A-Kaivin Oy | Construction | 1998 |
| Tampereen ATH-Service Oy | Other services | 1995 |
| Tampereen AV-Palvelu Oy | Construction | 1998 |
| Tampereen Aktiiva Oy | Real estate | 1989 |
| Tampereen Akvaariokala Oy | Wholesale & retail | 2019 |
| Tampereen Aluetaksi Oy | Transport & logistics | 1990 |
| Tampereen Ammatti-isännöitsijät Oy | Real estate | 1990 |
| Tampereen Arviointi- ja Toimitilapalvelu Oy LKV | Real estate | 1987 |
| Tampereen Arvo-omistus Oy | Real estate | 1999 |
| Tampereen Arvohuoneistot Oy | Real estate | 2001 |
| Tampereen Asema-Optiikka Suurkari Ky | Wholesale & retail | 1963 |