Tim's Mother is the unnamed mother of Tim. Although she isn't given a name, she appears in some BrainPOP episodes. She is seen with Tim in some episodes, and, by the events of the episode 'Voting', it can be safely said it is his mother. In the episode Immigration, it is revealed that she is of a Japanese descent.
Tim's mother seems to be in her mid-forties, hinting she may have been born in the 1960's. She married Tim's father some point in her life, maybe in her 20's, then had Tim.