In an open letter released by the "Let's Stay Together" campaign, the former England football captain says "my sincere hope is that you will vote to renew our historic bond which has been such a success over the centuries."
Beckham says "what unites us is much greater than what divides us."
Beckham played for Manchester United from 1992-2003 under a Scottish manager, Alex Ferguson. He also spoke of his pride at representing Britain in the bid team that secured the 2012 Olympics for London.
Beckham says "we worked together to bring the greatest sporting event of them all to our nation."
The Scottish independence referendum takes place Thursday.