Terrell Owens -- I'M GETTING MARRIED ... to a Postal Worker

Terrell Owens is finally gonna get his ring ... 'cause the former NFL star is GETTING MARRIED ... TMZ Sports has learned.

We know ... the 40-year-old wide receiver has obtained a marriage license in L.A. which shows he's planning to get hitched to Rachel Snider, a 33-year-old postal worker from Texas.

FYI -- Snider is NOT one of Terrell's FOUR baby mamas. As far as we know, they have no children together.

It's unclear how the two met ... but here's a shocker, it WASN'T on T.O.'s old VH1 reality show, which documented his (unsuccessful) search for the perfect mate.

As for the wedding, the marriage license is only good until April 8 ... so T.O. and Rachel have to swap "I dos" sometime before then, or else they'll have to apply for another license.

We're told the couple has been pretty hush hush about their engagement -- because, unlike Terrell, Rachel isn't obsessed with the spotlight.