No they are not brothers. J.R. Smith is the brother of Chris Smith (played at Manhattan and Louisville and on Knicks’ Summer League teams in 2012 and 2013, earning training camp invite in 2012 and 2013), and their father's name is Earl Smith Sr.
Josh Smith on the other hand is the son of Pete Smith; also an athlete who was one of the final cuts on the New York Nets in 1975.
J.R. Smith is currently at no. 5 - Guard-Forward for Cleveland Cavaliers. He has three brothers and two sisters. Aside from basketball, he also played football in high school and a dedicated golfer.
Josh Smith is currently no. 5 - Forward for Rockets. Has a brother, Walter and three sisters: Phebe, Kasola and Shanti.
He's interested in getting into sports broadcasting when his playing days are over, Smith took a step in that direction during the ‘06 Playoffs when he was selected by NBA TV to serve as a correspondent during the New Jersey-Indiana first round series
Tip! Find the latest updates on JR Smith and Josh Smith on Twitter @TheRealJRSmith and @JoshSmithFans.