By stealing second base in the fifth inning, Betts triggered Taco Bell's "Steal a Base, Steal a Taco" promotion.
That means everyone is the U.S. will get a free taco from the fast-food chain.
The free tacos will be available on Oct. 28, according to Taco Bell's website.
"TACOS ON ME!!!!" Betts said in a tweet Wednesday morning, urging fans to post their taco photos and tag him on Twitter.
Our Taco Hero has stolen a base. Now, America, you get to steal a free Doritos Locos Tacos. Steal yours 10/28.— Taco Bell (@tacobell) October 21, 2020
Betts led off the Dodgers fifth with a walk and then stole second. After NL Championship Series MVP Corey Seager drew a walk behind him, they pulled off a double steal.
"That's just another element that Mookie brings. He does a lot of studying to be able to create stress," Dodgers manager Dave Roberts said.
Then, with the Rays infield playing in, Max Muncy hit a bouncer to first baseman Yandy Diaz, who threw on the run after Betts broke quickly for the plate. He slid past the attempted tag for a 3-1 lead.
"It's just all practice," Betts said. "In BP, I run the bases. In spring training, we're running bases, constantly putting in this work for this time."
The only other player with a walk and multiple stolen bases in an inning during a World Series game was Babe Ruth in 1921.
"Stolen bases are a thing for me. That's how I create runs and create havoc on the basepaths," Betts said.
The Associated Press contributed to this report.