Nigeria international Iwobi penned a five-year deal which was only announced more than four hours after the transfer deadline.
The 23-year-old, capped 36 times by Nigeria, scored 15 goals in 149 appearances for Arsenal after making his first-team debut in 2015. New season alert, Start forecasting your Weekend games Now
“He is still young but already with a lot of top-level experience –- 100 Premier League matches, more in Europe and many international games,” said Everton manager Marco Silva.
Iwobi is the seventh new arrival at Goodison Park in the close season, following Italy striker Moise Kean – who joined from Serie A champions Juventus for €27.5 million – right-back Djibril Sidibe, midfielders Andre Gomes, Fabian Delph and Jean-Philippe Gbamin, as well as goalkeeper Jonas Lossl.
“Alex fits exactly the profile of player I want in my model,” added Silva.
Everton finished eighth in the Premier League last term to miss out on European qualification in Silva’s first season as boss.