Unai Emery won three straight Europa League titles at Sevilla and last season landed a domestic treble with Paris Saint-Germain.
Arsenal majority owner Stan Kroenke said: “We are delighted to welcome Unai to Arsenal. He’s a proven winner.
“We’re confident that he is the right person for the job and that he will work to deliver the triumphs our fans, staff and everyone who cares about Arsenal want.
“He shares our vision to move forward, to build on the platform created by Arsene Wenger and help this club enjoy greater success.”
Arsenal chief executive Ivan Gazidis says Unai Emery was the unanimous choice of the Arsenal board.
“Unai has an outstanding track record of success throughout his career, has developed some of the best talent in Europe and plays an exciting, progressive style of football that fits Arsenal perfectly.
“His hard working and passionate approach and his sense of values on and off the pitch make him the ideal person to take us forward.”