The 28-year-old, who joined the club's academy in 2003 and later made his debut in October 2005, has decided to prolong his stay for a further three years.
"I joined London Irish straight from school and the club have been brilliant to me over the last 10 years," Ojo told the club's official website.
"It's always an honour to wear the London Irish shirt and I'm looking forward to pushing on over the next three years with this group of players. The support I have received over the years has been amazing and I'm also looking forward to achieving many more milestones with the club."
Ojo will make his 200th appearance for London Irish against London Wasps in their Premiership clash on Saturday.