The 37-year-old goalkeeper has made over 400 appearances for the Toffees since his arrival from Manchester United in 2006.
However, Howard has now sealed a return back to his native America with the Colorado Rapids.
"I will remain an Evertonian for life. This will always be my team, my club," he told the Merseyside outfit's official website.
"I sacrificed so much to play the amount of games I have over a 10-year period, so I will continue to support this club that I love.
"The club is amazing, I love it and I will always be an Everton player."
Manager Roberto Martinez added: "Tim is such an incredible character. With certain players, their contribution goes a little bit further than starting in the team or not and Tim is probably the perfect case of that.
"He is such an influence on the young players. We had a really good group of young players coming through in the last three years and Tim has been a vital player in helping those players feel Everton and to understand what it takes to play in the team."
Howard has kept 131 career clean sheets from his 392 Premier League outings. body check tags ::