Which actress plays Lucas's younger sister Erica Sinclair in "Stranger Things"?

Priah Ferguson plays Lucas Sinclair's younger sister Erica Sinclair in "Stranger Things." Erica first appears in season 2 as Lucas's sharp-tongued younger sister and gradually becomes an important member of the fight against the Upside Down.

Initially, Erica is mostly known for her sarcasm, confidence, and love of ice cream. In season 3, Dustin and Steve recruit her knowledge of mathematics and her willingness to take risks to help infiltrate the secret Russian base beneath Starcourt Mall. Her memorable insistence that she is a nerd becomes part of the show's running joke about her interests.

Ferguson began acting in short films and television before joining the series. She was cast as Erica in 2017 and was promoted from a recurring role to a series-regular role in season 3. Lucas is portrayed by Caleb McLaughlin, while Max Mayfield is played by Sadie Sink. Grace Van Dien plays Chrissy Cunningham, and Millie Bobby Brown plays Eleven, so neither is Erica's actress.