|High School Mordecai and Rigby|
|Species:|| Blue Jay (Mordecai)
|Hair color:|| Brown (dyed) (Mordecai)
Blonde (dyed) (Rigby)
|Relatives:||Same as their present selves|
|Voiced by:|| J.G. Quintel (Mordecai)
William Salyers (Rigby)
|First appearance:||""A Skips in Time""|
|Latest appearance:||""Regular Show: The Movie""|
High School Mordecai and Rigby are the past selves of Mordecai and Rigby from 6 years ago, when the duo were in their senior year of high school. They have a cameo in "A Skips in Time" and they have a major role in "Regular Show: The Movie"
High School Mordecai has an abundant amount of brown hair, with some of it slightly touching his shoulders. He wears a white t-shirt, with a red collar and sleeve cuffs and the words "Brain Explosion", the name of Mordecai's favorite band, written on the front, with grey skinny jeans and red and white sneakers. During school he carries a navy blue backpack.
High School Rigby has bleached blonde hair (as stated by present Mordecai), which is a bit longer than his present self's hair and is styled down instead of spiked up, and is worn under a black trucker hat with the words "Fist Pump" written on the front, which is the name of his favorite band. He wears an olive green hooded jacket with a black shirt. During school, he carries an orange backpack.
- Unlike their present selves, they wear clothes, except High School Rigby is not fully clothed as he does not wear pants.
- High School Rigby's hair is bleached, as stated by present Mordecai.
- High School Mordecai rides a skateboard
- High School Rigby rides a bike.
- High School Rigby is seen to have two normal butt cheeks, as the punchies incident with Skips has not happened yet.
- On the DVD cover of Regular Show: The Movie, High School Mordecai is not wearing pants or sneakers.
- It is possible that the saxophone High School Rigby used to interrupt the volleyball state championship was High School Mordecai's, since he plays the saxophone.