The Switzerland international, 25, joined the Gunners from Servette in 2003 but has had loan spells at AC Milan and then Everton in the last two seasons.
He told Fulham's website: "I'm delighted that I am joining the club during the most successful period in its history."
The imposing Senderos will add another option for Cottagers boss Roy Hodgson at the heart of a defence already shorn of Chris Smalling this summer, while there is also speculation surrounding Brede Hangeland - who has been linked with a move in the opposite direction, to the Gunners.
Hodgson said: "Philippe is a player that I have admired for a very long time, since he captained Switzerland to the UEFA Under-17 Championship in 2002.
"He is a strong defender who has great aerial presence at both ends of the field and has a superb work ethic, which is a vital component for any team's success. I am very much looking forward to working with Philippe next season."
Those efforts eight years ago formed the start of Senderos' extensive experience of international competitions.
He was also part of the Swiss defence which did not concede a goal in the 2006 World Cup, played every minute of their Euro 2008 campaign on home soil and scored twice against Luxembourg as he helped his country reach this summer's World Cup in South Africa.
He will link up with Fulham after that campaign, having moved on a free transfer following the expiry of his contract at the Emirates Stadium.
He said: "I will be looking forward to meeting up with my new team-mates and of course, Roy Hodgson, a manager I respect very much, shortly after the World Cup.
"I very much hope that I can contribute over the next few seasons and that the club goes on to achieve more success."