Sabalenka won 6-2, 4-6, 6-3 against Gauff.
This victory marks her second consecutive Miami Open title.
Sabalenka also won the Indian Wells earlier this season.
Briefing: Sabalenka outlasts Gauff in 3 sets for Miami title
Strategic angle: Aryna Sabalenka earned her second straight title at the Miami Open with a hard-fought victory over Coco Gauff.