Series with the first letter - "T"
- The Old Man (2022–…)
- The One (2021–…)
- The Only Way Is Essex (2010–…)
- The Order (2019–…)
- The Original Ghostbusters (1986–1987)
- The Originals (2013–2018)
- The Orville (2017–…)
- The Osbournes Want to Believe (2020–…)
- The Other Two (2019–…)
- The Outer Limits (1963–1965)
- The Outer Limits (1995–2002)
- The Outlaws (2021–…)
- The Outpost (2018–…)
- The Outs (2012–…)
- The Outsider (2020–…)
- The Oval (2019–…)
- The Owl House (2020–…)
- The Pacific (2010)
- The Pacific War in Color (2018)
- The Pact (2015–…)
- The Pact (2021–…)
- The Pale Horse (2020–…)
- The Paper Chase (1978–1986)
- The Paradise (2012–2013)
- The Passage (2019–…)
- The Passing Bells (2014–…)
- The Path (2016–2018)
- The Patient (2022)
- The Pembrokeshire Murders (2020–…)
- The Penguins of Madagascar (2008–2015)