Principal Hendry is the unseen principal of Hendry Middle School. He and his office are the main weaknesses of Hendry Middle School as he greatly despises being disturbed in his office by anybody and anything. In Operation: E.L.E.C.T.I.O.N.S., Chad tried to stop Numbuh 1 during the battle between the elementary and middle school students after he learned that the principal's office is the weak point of the school. Numbuh 1 immediately fires a tennis ball at the office door, but it misses and Chad believed that he's got Numbuh 1. However the ball gets in Chad's path, causing his bike to slip and Chad to lose control and crash into Principal Hendry's Office. The principal is greatly outraged at Chad crashing into his office that he blows his top (both figuratively and literally). This causes the school to become too unstable to stay skyward and flips it sideways before finally crumbling to the ground.

Principal Hendry is voiced by Dee Bradley Baker