| Oy Quick Tech Ltd. | Helsinki | 1995 |
| Oy Quickels Ab | Helsinki | 1995 |
| Oy Quitas Ab | Helsinki | 1995 |
| Oy R Lemström Ab | Degerby | 2008 |
| Oy R-Wood Consulting Ltd | Suolahti | 1995 |
| Oy R. Österlund Ab | Helsinki | 1984 |
| Oy RAS-Marketing Ltd | Mäntyharju | 1988 |
| Oy RB Tribe Ab | Vaasa | 2022 |
| Oy RST's Ocean-Trade Finland Ltd | Seinäjoki | 1995 |
| Oy RVS Technology Ltd. | Helsinki | 2007 |
| Oy Raali Ltd | Turku | 1994 |
| Oy Race-Day, Nice-Day Motorsport Ab | Lepsämä | 1995 |
| Oy Radel Inc. Aktiebolag | Hyvinkää | 2020 |
| Oy Rakennusapteekki - Byggnadsapoteket Ab | Pohjankuru | 2016 |
| Oy Rapid Star Ltd | Rautio | 1989 |
| Oy Rasweco Ab | Helsinki | 1978 |
| Oy Rauta-Järn Österholm Ab | Lapinjärvi | 2006 |
| Oy Rautamo Ab | Pietarsaari | 1986 |
| Oy Re-Hab Finland Industries Ltd. | Helsinki | 1999 |
| Oy Really Pronto Ltd | Seinäjoki | 1996 |
| Oy Rehau Ab | Vantaa | 1973 |
| Oy Rengashuolto Lytz Ringservice Ab | Vaasa | 2014 |
| Oy Rengasliike Mobiroll Däckspecialist Ab | Lapväärtti | 1992 |
| Oy Renholm & Co Ab | Tuusula | 1996 |
| Oy Renom Ab | Espoo | 1998 |
| Oy Repco Andino Ltd | Espoo | 2006 |
| Oy Replicar Ab | Kerava | 1980 |
| Oy Resiterm Ab | Voolahti | 2002 |
| Oy Reuter & Stolt Products Ab | Espoo | 2004 |
| Oy Riitta Portman Ab | Karjaa | 1987 |
| Oy Rilarco Ab | Pirkkala | 1997 |
| Oy Ritel Marketing Ltd | Rauma | 1989 |
| Oy Roach Ab | Vaasa | 1981 |
| Oy Road Balance Ltd | Längelmäki | 2006 |
| Oy Roberts Ab | Turku | 2014 |
| Oy Rockdale Motors Finland Ltd | Nakkila | 2016 |
| Oy Rohdos Hälsa AB | Siuntio | 2024 |
| Oy Rohdos Kokkola Hälsa Ab | Kokkola | 2015 |
| Oy Roland Lauritzon & Co Ab | Sipoo | 2000 |
| Oy Rollfoods Ab | Vantaa | 1988 |
| Oy Roltrade Ab | Helsinki | 1986 |
| Oy Rondox Ab | Espoo | 2008 |
| Oy Ronitech Ab | Mustasaari | 1990 |
| Oy Rooi Ltd | Helsinki | 2014 |
| Oy Roomlight Ab | Espoo | 2008 |
| Oy Rufi Trade Ltd | Espoo | 1993 |
| Oy Rustung-Tarra Ab | Helsinki | 1982 |
| Oy Ruuskari Ab | Nastola | 2000 |
| Oy RydCap Ab | Vantaa | 2023 |
| Oy Rönnblad Electronik Ab | Tammisaari | 1997 |
| Oy S.Borg Invest Ab | Sipoo | 1982 |
| Oy S.O. Olenius Ab | Porvoo | 1971 |
| Oy S.W. Lauritzon & Co Ab | Helsinki | 1955 |
| Oy SCANENERGY Ltd | Porvoo | 2021 |
| Oy SL-Goods Ab | Oulu | 2012 |
| Oy SMM Beauty & Delight | Helsinki | 1996 |
| Oy SP-Gifts Ltd | Vantaa | 1998 |
| Oy STIGA Sports Suomi Ab | Espoo | 2010 |
| Oy STN Electronics Ltd | Espoo | 1995 |
| Oy SV Vacuumservice Ab | Helsinki | 1984 |
| Oy SaMa Kukkasitomo Ab | Vaasa | 2017 |
| Oy Saajos International Ltd | Lohja | 1992 |
| Oy Safewood Ltd | Hamina | 1997 |
| Oy Saidam Ab | Virrat | 2003 |
| Oy Sambakayaks Ab | Espoo | 2010 |
| Oy Samhita Ltd | Salosaari | 1995 |
| Oy Samooja Entertainment Ltd | Fiskari | 2012 |
| Oy Samson Ab | Vantaa | 1977 |
| Oy Sand Marketing Ab | Närpiö | 1986 |
| Oy Sand.W Steel Ab | Pietarsaari | 2015 |
| Oy Sandlin Ab | Pietarsaari | 1998 |
| Oy Sandman-Nupnau Ab | Järvenpää | 1920 |
| Oy Sanifer Ltd | Oulu | 2008 |
| Oy Santaco Sport Ltd | Järvenpää | 1990 |
| Oy Santtu Engineering Ltd | Vantaa | 1985 |
| Oy Satakunnan Vihanneskauppa Ab | Pori | 2026 |
| Oy Satex Ab | Helsinki | 1973 |
| Oy Satprint Ab | Helsinki | 1989 |
| Oy SatuGate Ab | Kemi | 2008 |
| Oy Savo Sport Center (SSC) | Leppävirta | 2007 |
| Oy Savonia Agency Ltd Ab | Siilinjärvi | 1981 |
| Oy Sawcenter Ab | Siuntio | 1989 |
| Oy Scan West Ab | Helsinki | 1992 |
| Oy Scan-Zhul Ab | Kouvola | 1995 |
| Oy Scancollection Ab | Helsinki | 1984 |
| Oy Scandiagent Forsström & Co Ab | Helsinki | 1997 |
| Oy Scandic Levels Ab | Nokia | 1992 |
| Oy Scandic Trading House Ltd | Tampere | 2007 |
| Oy Scandinavian Merchandise Center broking & trading Ltd. | Imatra | 1985 |
| Oy Scandinavian Trade & Service Company Ltd | Helsinki | 1998 |
| Oy Scandinavian Wool and Silk Import Ltd | Espoo | 2007 |
| Oy Scandisol Ab | Kalliola | 1993 |
| Oy Scandrive Ltd | Espoo | 1992 |
| Oy Scanex Medical Systems Ab | Parainen | 1995 |
| Oy Scanhomes Ltd. Finland | Harjavalta | 1995 |
| Oy Scanica Ab | Espoo | 2002 |
| Oy Scanrus Ltd Ab | Helsinki | 1995 |
| Oy Scanteknik Ab | Kirkkonummi | 1993 |
| Oy Schulmanin Taideliike - Schulmans Konsthandel Ab | Helsinki | 1997 |
| Oy Sda Finland Ltd | Raisio | 1992 |