If they're NOT dating by now ... they should be. 

Blake Griffin and Kendall Jenner went out to a fancy romantic dinner AGAIN -- this time, they were joined by fellow NBA star Chandler Parsons and Hailey Baldwin.

Blake and Kendall left Craig's in L.A. together and got into a waiting car. Chandler followed shortly after. Hailey was definitely with the group ... but didn't want to be part of the mass exodus. 

Chandler and Hailey have been spotted together in the past (sunbathing together in June) but insist they're not exclusively dating. 

Blake and Kendall have been spending a lot of time together, too. But no official confirmation there either. 

Bottom line -- four attractive, rich, famous people hanging out. What do YOU think is happening?