The teenager will now become the youngest player to compete in the last-16 after storming past a player ranked 102 places above him.
The 16-year-old will now become the youngest player to compete in the last 16 after breezing past a player ranked 102 places above him.
Littler stormed into a 2-0 lead after winning all six legs, and held his nerve to come from two legs down in the third set to win a final leg decider 3-2.
Campbell appeared to stage a remarkable fightback after Littler missed a match dart at bull off 91 to win the fourth set 3-2, but then lost two throws in the fifth set as the debutant hit a double 20 to see out the match 4-1.
The world youth champion had already beaten 2012 BDO champion Christian Kirstand in the opening round and UK Open champion Andrew Gilding the following day on his way to the third round.
He will now face either Wales' Jim Williams or former champion Raymond van Barneveld on Saturday for a place in the quarter-final.
"Unbelievable! I only wanted to win one game and I've won three," Littler told Sky Sports. "I've battled through it and I'm so happy. I just let my darts do the talking.
"As soon as I won that first game against Christian Kist I just settled. As soon as I went 2-0 up against Matt I tried to calm myself down because last time it didn't go too well. I kept composed and got over the line."
