Chief Executive Rick Parry, speaking to the club's official website, said: "This extension to the current deal consolidates the partnership with Reebok as our premier sponsor.
"Over the years we have developed an excellent relationship with Reebok and we are looking forward to expanding our association on a global basis."
The two partners also hope to increase the club's profile in North America and Asia.
Martin Coles, chief executive and president of the sportswear giants, added: "Reebok is extremely excited to align with such a global soccer powerhouse.
"Our goal is to build Liverpool FC into the premier football brand in the world. This deal adds to our mission of being the best sports performance and sports lifestyle company in the world."