The 17-year-old had qualified ninth for the final but took home the title with a score of 330.75 points – four points clear of Russia's Anna Chuineyshena in second.
The gold medal continued a strong start to the year for the Leeds diver who won a hat-trick of British titles in Edinburgh last month.
“I didn’t expect this victory,” said Toulson, who competed alongside Tonia Couch at the 2016 Olympics.
“I’ve been training very hard recently and was able to improve my dives.
“I am not totally satisfied with my dives yet. But I also gained a lot of experience here for the upcoming World Championships in Budapest.”
Toulson also competed in the team event in Kiev where she finished sixth after scoring 351.20 points alongside City of Leeds teammate Matty Lee.
Toulson's attention will now focus on the World Championships which take place in Budapest, Hungary from 14 July. She is expected to compete alongside Couch in the 10m sychronised event and in the 10m Platform.