The debate over the NBA's anniversary team has begun -- with Klay Thompson PISSED over getting snubbed from the list.

88 voters -- ranging from people like Michael Jordan to Stephen A. Smith -- selected 75 players they think are NBA's greatest.

The league revealed the list (which ended up being 76 players because of a tie) this week for their 75th anniversary ... and the Golden State Warrior sharp shooter didn't make it.

"Maybe I'm just naïve in my ability to play basketball," the 31-year-old said of being off the list on Thursday.

"But in my head, I'm TOP 75 of all time."

Is he naïve, though? Well, let's take a look ...

Thompson is a 3x champ, 5x All Star, holds the record for most points in a quarter, the most 3 pointers made in a game and ties the record for most 3-pointers made in a single playoffs (98) with his teammate Stephen Curry -- who made the list.

Warriors head coach Steve Kerr agrees with Thompson ... and feels Draymond Green should be on there too, saying, "I definitely think that both guys are top 75."

"Just based on winning and two-way basketball and everything that really matters more than statistics. What matters is if you’re winning championships, that’s what counts."

To be fair, selecting only 75 players is a pretty tough task ... and many, who would be considered top level, didn't make the cut.

Some notable names ... Grant Hill, Vince Carter, Tracy McGrady, Penny Hardaway and Dwight Howard also got left off the list.

At the end of the day, should Thompson be up there?? Maybe he'll make the 100-year anniversary list.