Yhtyneet Paperitehtaat
| United Paper Mills Ltd. (English translation) | |
| Formerly | Ab Simpele Jämsänkoski Oy, Myllykoski Träsliperi Ab, Ab Walkiakoski Oy |
| Company type | Former Public Limited Company |
| Industry | Forest industry, Pulp and Paper |
| Predecessor | Ab Simpele Jämsänkoski Oy, Myllykoski Träsliperi Ab, Ab Walkiakoski Oy |
| Founded | 1920 in Finland |
| Founder | Rudolf Walden |
| Defunct | 1996 (merged) |
| Fate | Merged with Kymmene Oy to form UPM-Kymmene |
| Successor | UPM-Kymmene Oyj |
| Headquarters | Finland, Finland |
Area served | International |
Key people | Rudolf Walden (founder, chairman 1920–1944), Juuso Walden (managing director 1940–1969), Niilo Hakkarainen (managing director 1970–1991), Olli Parola (managing director 1990–1995) |
| Products | Paper, Pulp, Cardboard |
| Parent | Repola Oy (prior to merger) |
Yhtyneet Paperitehtaat Oy was a Finnish forest industry company which was created in 1920 and the paper company formed UPM-Kymmene PLC together with Kymmene in 1996.