Onavo, founded in 2010, published a notice on its blog.
"We are excited to join their team, and hope to play a critical role in reaching one of Internet.org's most significant goals -- using data more efficiently so that more people around the world can connect and share. ... Onavo's Tel Aviv office will remain open for business and will become Facebook's new Israeli office," the company's co-founders, Guy Rosen and Roi Tiger, wrote on the blog.
Details of the agreement were not disclosed. Haaretz said the purchase price was more than $100 million.
Onavo developed Insights, the first mobile market intelligence service.
The company said its mobile apps "take the worry out of using smartphones and tablets."
The agreement marks the first time Facebook will run a research and development center in Israel, the newspaper said.