The gymnastics star took to Instagram to send the message to the haters on Sunday night ... after they had crawled out yet again following the NFL player's appearance at her competition on Saturday in Hartford, Connecticut.

You'll recall, the NFL safety has received heat from fans ever since he referred to himself as "the catch" in the couple's relationship while doing an interview on the "The Pivot" back in December ... and when he was shown on TV as "Simone Biles' Husband" at the event over the weekend, the negative comments cropped up again all over social media.

Eventually, they got back around to Biles -- who, by the way, dominated at the event -- and she made it apparent, she's tired of hearing about it.

"I'm going to quickly address this," she wrote on her Stories, "the joke was never a joke! Y'all are blatantly being disrespectful to my relationship & my husband. So I'm gonna go ahead and say this one time. Respectfully, f*** off."

"& if you keep commenting or tweeting at me I'm just going to block you. Simple as that."

It's not the first time she's raced to Owens' defense ... she just did it last month too -- when she made a TikTok video pretending to put tape on the football player's detractors' mouths.

Biles also threw her support behind her man in an Instagram post Sunday morning following the event in Connecticut, calling Owens "the best supporter."

"I couldn’t ask for a better husband," she added.