The tattoo on xXx's leg bears the name "Harry O'Connor". Harry O'Connor was a stuntman featured in xXx (2002), who died during filming. He was the stuntman who doubled for Xander Cage during the famous parachute zip-wire stunt in Prague.
Originally, this movie was going to be a direct sequel to xXx (2002), ignoring xXx: State of the Union (2005).
Actress Nina Dobrev, a genuine thrill seeker by her own admission, was so displeased to see that her character in this film was going to be just some "tech geek", that she kept asking director D.J. Caruso to give her some kind of an action scene until he gave in and added a part where she gets to use a gun. However, because this hadn't been the plan, she became the only cast member in an action scene to not get any sort of gun training beforehand.
Bollywood actress Deepika Padukone made her Hollywood debut with this movie. Reportedly, she had turned down an offer to work on Furious 7 (2015) after unavailability of dates.