| Octago (Yvio) (2008) | Reiner Knizia | Public Solution GmbH | report (26.07.2012, Walter) | 5.0 |
| Oddville (2012) | Carlo Lavezzi | What's Your Game? | report (14.02.2013, Walter) | 4.8 |
 Odin (2024) | Yohan Goh,
Hope S. Hwang,
Gary Kim | Helvetiq | report (16.10.2024, Walter) | 8.0 |
| Ogallala (1989) | Rudi Hoffmann | Altenburger Spielkartenfabrik | review (31.08.2005, Walter)report (31.08.2005, Walter) | 4.4 |
| Oh My Goods! (2015) | Alexander Pfister | Lookout Games | report (02.09.2017, Walter) | 4.3 |
| Ohanami (2019) | Steffen Benndorf | Nürnberger Spielkarten | report (20.02.2019, Aaron)report (13.02.2019, Walter) | 5.5 |
| Ohne Furcht und Adel (2000) | Bruno Faidutti | Hans im Glück | report (31.08.2002, Aaron)report (20.08.2002, Peter) | 7.4 |
| Öl für uns alle (1976) | Tord Hasselquist | Ravensburger Spieleverlag | report (11.09.2002, Aaron) | 2.2 |
| Old London Bridge (2022) | Leo Colovini,
Gabriele Bubola | Queen Games | report (11.01.2023, Walter) | 5.0 |
| Oltre Mare (2004) | Emanuele Ornella | Mind the Move | review (17.11.2004, Walter) | 7.8 |
| Olympos (2011) | Philippe Keyaerts | Ystari | report (28.12.2011, Walter) | 7.3 |
| Olympus (2010) | Andrea Chiarvesio,
Luca Iennaco | Fantasy Flight Games,
Heidelberger Spieleverlag | report (09.08.2013, Walter)report (04.08.2013, Aaron) | 7.0 |
| On The Cards (2011) | Sebastian Bleasdale | Surprised Stare Games | report (16.02.2012, Walter) | 4.8 |
| On the Road (2023) | Leo Colovini,
Gabriele Bubola | Helvetiq | report (10.07.2024, Walter) | 5.0 |
| On The Underground (2006) | Sebastian Beasdale | JKLM Games | review (02.09.2007, Walter)report (18.07.2007, Walter)report (17.01.2007, Walter) | 6.3 |
| Once Upon A Time (1993) | James Wallis,
Andrew Rilstone,
Richard Lambert | Atlas Games | report (09.12.2003, Aaron) | 4.7 |
| One Week Ultimate Werewolf (2018) | Ted Alspach,
Akihisa Okui | Bézier Games | report (15.05.2019, Walter) | 3.3 |
| Opera (2009) | Hans van Tol | HUCH & friends,
The Game Master | report (11.02.2010, Walter) | 7.0 |
| Ora et Labora (2011) | Uwe Rosenberg | Lookout Games | report (19.01.2012, Walter)report (05.01.2012, Walter) | 6.5 |
| Orcz (2000) | Christian T. Petersen,
Greg Benage | Fantasy Flight Games | review (31.12.2001, Moritz) | 6.0 |
| Order Overload Cafe (2022) | Jun Sasaki | Oink Games | report (27.09.2023, Walter) | 4.0 |
| Oregon (2007) | Åse Berg,
Henrik Berg | Hans im Glück | report (08.05.2008, Walter) | 4.2 |
| Origins of World War II (1971) | James F. (Jim) Dunnigan | Avalon Hill | review (31.12.2001, Moritz) | 4.0 |
| Orléans (2014) | Reiner Stockhausen | dlp Games | report (26.03.2015, Walter) | 6.5 |
| Otys (2017) | Claude Lucchini | Libellud,
Pearl Games | report (23.02.2018, Walter)report (17.02.2018, Walter) | 6.0 |
| Outpost (1991) | James Hlavaty,
Tim Moore | TimJim Games | report (07.05.2003, Walter)report (29.01.2003, Walter)report (29.01.2003, Walter) | 6.4 |
| Overthrone (1999) | Frank DiLorenzo,
Stacey Merrill | R&R Games | review (01.10.2001, Moritz) | 4.7 |
| Ozeanien (2004) | Klaus Teuber | Klaus Teuber Classics | review (11.11.2004, Peter) | 2.0 |
