Facebook did not disclose a price for the San Francisco-based company, which was founded in 2007 and has offices in several countries.
LiveRail's technology automatically pairs video ads with the videos that appear on many websites, such as the sites for Major League Baseball, ABC and A&E Networks.
Facebook would not discuss plans for using the technology on its own website.
"What LiveRail ultimately offers is a complete advertising solution for video publishers," Facebook Vice President of Ads Product Marketing, Brian Boland, said in a blog post.
"We believe that LiveRail, Facebook and the premium publishers it serves have an opportunity to make video ads better and more relevant for the hundreds of millions of people who watch digital video every month."
In March, Facebook began offering 15-second video ads from a limited number of companies on its website. The company has moved cautiously in introducing the video ads on its social network to prevent a backlash from users who might find the ads annoying.
Video ads command higher prices than other forms of online advertising such as banner ads. Facebook and Internet rivals like Google Inc are increasingly trying to grab a slice of lucrative TV-marketing budgets as they try to sustain rapid growth.
Written with agency inputs