Williams made it clear, however, that he will continue to be team principal for the squad that bears his name.
But he said it is time for him to start the process of handing over the reins of the team since he will turn 70 next month.
"This is an opportune moment for me to consider my own role in the team," he said. "I turn 70 in April and I have decided to signal the next stage in the gradual but inevitable process of handing over the reins to the next generation by stepping down from the Board at the end of this month.
"This is not as dramatic a move as it may appear: I shall continue to work full-time as Team Principal and I shall continue to attend all Board meetings as observer. I also remain the majority shareholder of Williams Grand Prix Holdings PLC."
Williams co-founder Patrick Head left the board at the end of last year.
The team also announced that Claire Williams will join its board from 1 April as director of marketing and communications.