|Other family:||Chloe O'Brian (sister-in-law)|
Prescott O'Brian (nephew)
|Mentioned in:||"Day 6: 12:00pm-1:00pm"|
Timothy O'Brian was the younger brother of Morris O'Brian. Darren McCarthy released false information that Timothy was being administered to the hospital due to radiation poisoning to draw Morris out into the open. By the time CTU figured out what McCarthy was doing, Morris had already been kidnapped by McCarthy.