The Karate Kid star attended this week's ceremony in Westlake Village, California with his sister Willow and parents Will and Jada Pinkett.
WENN reports that the entire family were "beaming" as the 18-year-old left Oaks Christian High School, but it was Jaden who first extended his congratulations online.
He wrote on Twitter: "My Big Bro Just Graduated, I'm Cryin g#Sike #RealGs Don't Cry (sic)".
'Whip My Hair' singer Willow was next to praise her older sibling on the social networking site, tweeting: "Congratulations to my big brother Trey on his graduation!! <3 you!!"
Also on hand to watch Trey graduate was his mother Sheree Zampino, who was married to Hancock star Will between 1992 and 1995.
Will previously boasted that his family always come "number one" in their endeavours.