Who voiced GLaDOS in Portal and Portal 2?

Ellen McLain voiced GLaDOS in both Portal and Portal 2. Her performance defines the character's distinctive style: a calm, polished computer voice delivering scientific instructions, dry jokes, and increasingly alarming threats.

GLaDOS first appeared in Portal, released in 2007, as the automated system supervising Chell's testing. McLain returned for Portal 2 in 2011, where the story explores GLaDOS's history, her relationship to Aperture Science, and her connection with Caroline. The same voice actor helps make that identity reveal recognizable even before every detail is explained.

McLain also performed the voices of Aperture's sentry turrets and sang the end-credit song “Want You Gone” for Portal 2. Chell, the player character, does not speak, which makes GLaDOS's voice especially central to the series. Tara Strong and Jennifer Hale are sometimes suggested because they are prominent game voice actors, but neither voiced GLaDOS.