Oklahoma City Thunder guard Josh Giddey will not face charges stemming from a police investigation into whether he had an improper relationship with an underage girl ... TMZ Sports has learned.
Newport Beach PD tells us the case -- which was launched back in November -- is officially closed ... after officials found no corroborating evidence.
In other words, no one involved was willing to talk ... and 21-year-old Giddey is in the clear.
As we previously reported, Giddey was the center of serious allegations made on social media during Thanksgiving weekend .