The 43-year-old has been brought in as a replacement for Rafael Benitez, who was sacked a fortnight ago for non-performance.
Lampard had been out of management for over a year following his dismissal as Chelsea boss. The former England midfielder led the Blues to fourth position in his first season in charge but struggled in his second term.
Everton are in 16th position on the Premier League table, four points above the relegation places.
"It is a huge honour for me to represent and manage a club the size and tradition of Everton Football Club," Lampard said after his appointment was confirmed on Monday.
"I'm very hungry to get started. After speaking to the owner, Chairman and the Board, I very much felt their passion and ambition. I hope they felt my ambition and how hard I want to work to bring it together.
"You can feel the passion Everton fans have for their club. That will be hugely important.
"As a team – the competitive level that the Premier League brings and the position we are in the table – we certainly need that.
"It's a two-way thing. I think Everton is a unique club in that you can really understand what the fans want to see. The first thing they want is fight and desire and that must always be our baseline.
"My first message to the players will be that we have to do this together. We'll try to do our job and I know the fans will be there backing us."
Lampard’s first game in charge of Everton will be against Brentford in the FA Cup after the international break.
