Peaty had already secured the men's 100m breaststroke and 4x100m mixed medley relay titles in Germany and went into Saturday's 50m breaststroke final as the clear favourite.
That came about after a run through the earlier rounds which saw him set a new championship record in the heats before replacing that with a new world record of 26.62 seconds in last night's semi-finals.
And while the pace was slightly slower in the medal showdown, Peaty was not to be beaten, touching in a time of 27.00 seconds, with Lithuania's Giedrius Titenis in second and Slovenia's Damir Dugonjic taking bronze.
The Europeans are only Peaty's second major international event after taking double gold and silver at the Commonwealth Games but the 19-year-old was already turning his attention to Rio 2016.
"I'm really happy with winning that one," he said. "It was a bit slower than my heats and the semis, but I was coming off a massive high last night - a high I've never experienced before.
"Hopefully come the Olympics I can fine-tune that and get stronger through the rounds."
Peaty's gold meant the Great Britain team surpassed their previous best of 18 medals at a single European Championships set at Budapest 2010.
Earlier they had equalled that mark as Fran Halsall edged out team-mate and Commonwealth Games champion Georgia Davies by one hundredth of a second to take 50m backstroke gold.
Halsall, who had already won gold alongside Peaty in the mixed relay and 50m butterfly bronze, recorded a new personal best of 27.81 seconds in an event she does not count as one of her main events.
"I don't know how that happened," said Halsall, who will go for another medal in the 50m freestyle final on Sunday.
"It was just a fun event where I wanted to see how I could do.
"I was hoping to dip under 28 seconds, and I did that and managed to get a gold medal, so I can't complain.
"It's just on the day who gets their fingernails on the wall first and today it was me."
Elsewhere Adam Barrett just missed out on a medal after touching in fourth place in the 100m butterfly and Ben Proud progressed to tomorrow's 50m freestyle final as the second fastest qualifier.
- Swimming & Diving
- Sports & Recreation
- Fran Halsall
- Commonwealth Games