Millie Davis ( born December 6 , 2006 ) is a Canadian actress who is best known for her roles as Ms. O in the PBS Kids series '' Odd Squad '' , Summer in the film '' Wonder '' , and Gemma Hendrix in the series '' Orphan Black '' . She was nominated for a Best Actress award as Ms. O in '' Odd Squad : The Movie '' at the 5th Canadian Screen Awards and has been co-nominated with the '' Odd Squad '' cast for four additional awards , including winning the award for " Best Young Ensemble in a TV Series " at the 2015 Joey Awards
5th Canadian Screen Awards
5th Canadian Screen Awards
Millie Davis