Various voice actors in play multiple roles in Amphibia, with several notable examples being.
- Eden Riegel voices Maggie, Lydia, Wartilda, and several other incidental female voices throughout the series.
- Sumalee Montano voices Mrs. Wu, a couple of the mothers seen in "Hop Til You Drop", and one of the unnamed female townspeople in "Reunion".
- April Winchell voices Tuti, Fens, Mrs. Virk, Fern, and Braddock in season 2.
- In addition to voicing Hop Pop, Bill Farmer has also provided various other incidental voices, with the most notable being the Mudmen in "Anne vs. Wild".
- Troy Baker voices Captain Grime, the Frog Bots seen throughout season 3, various incidental townspeople in Wartwood and Earth, and the Cloak-bot.
- Brian Sounalath voices Mr. Boonchuy and various incidental humans in season 3.
- Amanda Leighton voices Polly as well as various unnamed female townspeople in a couple episodes in season 1.
- In general, all the townspeople's voice actors have voiced a couple of incidental characters in addition to their usual roles.
- Matt Braly voices Chuck and Frobo.
- If there is an incidental male voice in the series not done by Troy Baker or Bill Farmer, expect it to be Sam Riegel.
- Kari Wahlgren voices Martha, Juniper, and Juliet in "A Night at the Inn", the computer voice in "Fort in the Road", the female volleyball player in "Marcy at the Gates", and Professor Scalini and one of the guards in "Sprig Get Schooled".
- Dee Bradley Baker voices both Bessie And Microangelo in the titular episode.
- Alex Hirsch voices the Curator and Frog Soos, both being expies of characters he voiced.
