mathew knowles baby*Say it ain’t so. Beyonce‘s dad, Mathew Knowles, is being called a “Deadbeat Dad.”

You heard us.

This according to the mother of his 3-year-old son, Nixon, who claims Mathew Knowles has stiffed her out of $24k in child support, according to TMZ, who got a hold of California State records showing Knowles has missed TWO of the $12k monthly payments he’s been ordered to pay to Alexsandra Wright.

Sources close to Wright says she’s in a financial bind and needs the cash asap — we’re told she even had to pull her son from school because she can’t afford the tuition.

As has been reported … the legal battles between Knowles and Wright have been ugly. She claims Knowles sent a threatening email to her in 2011 … warning “there’s a price to pay” for hurting his family.

We reached out to Mathew for comment — so far, no word back.

Read more here.