Les Moonves won't face criminal charges for a woman's claims he sexually abused her in the late '80s ... according to the L.A. County D.A.'s office.
The CBS honcho's accused of 2 separate incidents of sexual assault -- one in 1986 and one in 1988 -- by an unidentified woman who went to cops in February.
The woman -- listed as an acquaintance who knew Moonves through her job in the TV industry -- claims the 1986 incident included forced oral sex, and the 1988 allegations include indecent exposure and assault.
But, according to the D.A. ... the statute of limitations has expired for all of the alleged incidents, so prosecutors are declining to pursue charges.
As we reported ... CBS is investigating various accusations of sexual misconduct from 6 women against Moonves that were revealed in a New Yorker article last week.