| Year | Title | Role | Notes |
| 1984–1992 | Who's the Boss? | Samantha Micelli | Main role, 196 episodes |
| 1986 | The Canterville Ghost | Jennifer Canterville | Television film |
| 1988 | Crash Course | Vanessa Crawford |
| Dance 'til Dawn | Shelley Sheridan |
| 1989 | Living Dolls | Samantha Micelli | 2 episodes |
| The Making of The Little Mermaid | Herself (Host) | TV special |
| 1993 | Casualties of Love: The Long Island Lolita Story | Amy Fisher | Television film |
| At Home with the Webbers | Fan |
| Candles in the Dark | Sylvia Velliste |
| 1994 | Confessions of a Sorority Girl | Rita Summers |
| 1995 | The Surrogate | Amy Winslow |
| The Outer Limits | Hannah Valesic | Episode: "Caught in the Act" |
| 1996 | Mr. Show with Bob and David | Audience member | 2 episodes |
| To Brave Alaska | Denise Harris | Television film |
| 1997, 2001 | Spin City | Meg Winston | 2 episodes |
| 1997–1998 | Melrose Place | Jennifer Mancini | 40 episodes (seasons 5–7) |
| 1998 | Goldrush: A Real Life Alaskan Adventure | Frances Ella 'Fizzy' Fitz | Television film |
| Fantasy Island | Gina Williams | Episode: "Superfriends" |
| 1998–2006 | Charmed | Phoebe Halliwell | Main role; 178 episodes; also producer (seasons 5–8) |
| 2001 | The Diamond Hunters | Tracy Van der Byl | Miniseries |
| Family Guy | Herself (live-action) | Episode: "Mr. Griffin Goes to Washington" |
| 2004 | The Adventures of Jimmy Neutron: Boy Genius | April the Gorlock (voice) | Episode: "Win, Lose and Kaboom" |
| 2007–2008 | My Name Is Earl | Billie Cunningham | 10 episodes (season 3) |
| 2008 | Wisegal | Patty Montanari | Television film; also producer |
| 2010 | Castle | Kyra Blaine | Episode: "A Rose for Everafter" |
| Kick Buttowski: Suburban Daredevil | Scarlett Rosetti (voice) | Episode: "Frame Story/And... Action!" |
| Sundays at Tiffany's | Jane Claremont | Television film; also producer |
| 2010–2011 | Romantically Challenged | Rebecca Thomas | 6 episodes |
| 2011 | Young Justice | Poison Ivy (voice) | Episode: "Revelation" |
| 2011–2012 | Breaking In | Amy | 2 episodes |
| 2013–2014 | Mistresses | Savannah "Savi" Davis | Main role (seasons 1 & 2), 26 episodes |
| 2013–2016, 2018–2019 | Project Runway All Stars | Herself/host | Judge |
| 2014 | Hollywood Game Night | Herself | Episode: "Things That Go Clue-Boom in the Night" |
| 2015 | RuPaul's Drag Race | Herself | Judge |
| 2017 | Wet Hot American Summer: Ten Years Later | Renata Murphy Delvecchio | 5 episodes |
| 2018–2019 | Insatiable | Coralee Armstrong | Main role, 18 episodes |
| 2019 | Tempting Fate | Gabby Cartwright | Television film |
| Grey's Anatomy | Haylee Peterson | Episode: "Reunited" |
| 2020 | Celebrity Call Center | Herself | Episode: "The Shift With the Brony" |
| You Are My Home | Sloane | Television film |
| 2021 | The Now | Sarah | 3 episodes |
| 2025 | Elsbeth | Lisette "Pupetta" Del Ponte | 2 episodes |
