Dwyane Wade and Gabrielle Union Support 11-Year-Old Son at Gay Pride Parade

Gabrielle Union was dancing her ass off at the Pride Festival in Miami Beach this weekend ... and it was all to show support for her 11-year-old stepson, Zion.

Zion is Dwyane Wade's son from a previous relationship but he lives with Dwyane and Gabby full-time and Gabby treats him like blood.

While Wade wasn't at the event -- the Miami Heat had a game in Toronto -- the NBA star was certainly proud of his family, saying:

"Zion had his own cheering section today. Wish I was there to see you smile kid."

The Pride Festival in Miami Beach is one of the biggest LGBTQ events in the country -- with more than 145,000 people flocking to South Beach last year to celebrate together.

Gabby was having a blast -- dancing, taking pictures with fans and signing autographs.

Zion was sporting a rainbow ribbon and a big ol' smile!

Dwyane posted a photo of his older son, Zaire -- a HUGE prep basketball star -- with Zion at the parade along with the caption, "We support each other with pride."

He added, "It's a family thing."