Sally MacGill is a 16 year old babysitter who sometimes babysits Arthur, D.W., and Kate Read. She is usually lighthearted and fun, but in Arthur's Babysitter Drama she was crabby and depressed because she and her boyfriend Corey had recently broken up.

In Sally's original appearance in the Arthur episode Crushed, Arthur has a crush on Sally but is disappointed to discover that she already had a boyfriend.

In Arthur's Babysitter Drama, Sally reveals to Arthur that she and Corey had broken up. Before Arthur can act, Corey returns to apologize to Sally. Corey thinks that Sally is cheating on him with Arthur, so he goes ballistic.

Sally was seen in the crowd of the inter-species rally on February 12, 2015. She was raising her hand to a symbol of respect, like the rest of the crowd. She then participated in the Inter-Species Revolution.