Dez Bryant -- My Twitter Hashtag ... Deserves a Trademark

Dez Bryant is gunning to trademark his famous Twitter hashtag -- #ThrowUpTheX" -- in an effort to make sure he controls the use of his slogan on social media ... TMZ Sports has learned.

FYI -- the Dallas Cowboys star has been throwing up an "X" signal with his arms as a TD celebration for years ... and it's become his signature move with fans who often tweet pics of themselves to Dez "throwing up the X."

Now, we've learned Dez has filed documents with the United States Patent and Trademark Office ... looking to trademark #ThrowUpTheX for use in "news bulletins."

We did some digging ... and essentially, the "news bulletins" category covers computer software and other digital platforms that seems to cover social media.

So why trademark a hashtag? We spoke with Dez's rep who says they want to make sure no one else can take the hashtag and use it for unapproved non-Dez related activities.

Bryant has also started a "Throw Up The X" clothing line ... and we're told he hopes to grow the brand into an Under Armour-type company ... eventually signing other stars to endorsement deals.

Currently, the trademark for #ThrowUpTheX is pending -- and could take months until officials make a decision.