Jenner, 18, got cozy with Dallas Mavericks small forward Chandler Parsons while dining with little sister Kylie, sports agent Dan Frank and another female friend at STK LA on Saturday night.
Sipping water and eating on tuna tartare, the Givenchy model focused her attention on Parsons throughout the night.
"They were heavily flirting, but no touching," an onlooker tells PEOPLE. "Chandler and Kendall were talking the whole time. His agent was chatting with Kylie and the other friend."
Parsons, 25, played for the University of Florida on an athletic scholarship before being drafted by the Houston Rockets in 2011. He signed with the Mavericks earlier this month.
He's also no stranger to the fashion world: The 6-foot-9-inch athlete can be seen on billboards modeling Buffalo Jeans.
Jenner has been linked to rapper Young Jinsu and One Direction's Harry Styles.
Reporting by MELODY CHIU