| Year | Title | Role | Notes |
| 1994 | Chicago Hope | Dr. Wendy Smythe | Episode: "Genevieve and Fat Boy" |
| 1994 | The 5 Mrs. Buchanans | Zena | Episode: "Bad News Bert: There's Peanuts in the Peanut Butter" |
| 1995 | Hearts Afire | Margot | Episode: "John and Georgie's Not-So-Excellent Adventure" |
| 1996 | London Suite | Grace Chapman | Television film |
| 1996–2001 | 3rd Rock from the Sun | Sally Solomon | 139 episodesPrimetime Emmy Award for Outstanding Supporting Actress in a Comedy Series (1997, 1999)Nominated—Primetime Emmy Award for Outstanding Supporting Actress in a Comedy Series (1998)Nominated—Golden Globe Award for Best Supporting Actress – Series, Miniseries, or TV Film (1997)Nominated—Screen Actors Guild Award for Outstanding Performance by a Female Actor in a Comedy Series (1997)Nominated—Screen Actors Guild Award for Outstanding Performance by an Ensemble in a Comedy Series (1997—1999) |
| 1997 | Microscopic Milton | Narrator | US version |
| 1998–2000 | Hollywood Squares | Herself | Panelist; 10 episodes |
| 2004 | Sex and the City | Lexi Featherston | Episode: "Splat!" |
| 2005 | ER | Head Nurse Eve Peyton | 6 episodes |
| 2007 | Kim Possible | Warmonga (voice) | 3 episodes |
| 2009 | The New Adventures of Old Christine | Francie | Episode: "Too Close for Christine" |
| Ab Fab | Patsy | US remake of Absolutely Fabulous. Pilot episode only. Series not picked up. |
| 2009–2010 | Ugly Betty | Helen | 3 episodes |
| 2010 | Bored to Death | Mistress Florence | Episode: "Escape from the Dungeon!" |
| 2011–2015 | The Exes | Holly Franklin | Gracie Award for Outstanding Female Actor in a Leading Role in a Comedy or Musical Main role; 64 episodes |
| 2013 | RuPaul's Drag Race | Herself | 2 episodes |
| 2014 | Kirstie | Waitress Maddie | Episode: "Maddie vs. Maddie" |
| Modern Family | Brenda | Episode: "Strangers in the Night" |
| 2015 | Getting On | Marla Pounder | Episode: "Please Partake of a Memorial Orange" |
| 2017 | Daytime Divas | Anna Crouse | 6 episodes |
| 2018–2021 | Mom | Tammy Diffendorf | 57 episodesGuest: Season 5; Recurring: Season 6; Main: Seasons 7–8 |
| 2019 | Amphibia | Braddock (voice) | Episode: "Prison Break"; replaced by April Winchell afterwards |
| 2022 | Our Flag Means Death | The Widow Evelyn Higgins | 2 episodes |
| 2023 | The Righteous Gemstones | May–May Montgomery | 9 episodes |
| 2025 | Leanne | Carol | Main role, 16 episodes |
