The La Liga side have made the decision in the wake of Monday's 4-0 loss at struggling Leganes, the club's third successive defeat.
Betis currently sit 15th in the La Liga table, although they are safe from relegation as they lie 10 points clear of the bottom three with two games left.
It has also been announced that Alexis Trujillo, the club's technical secretary, will take charge for the matches against Atletico Madrid and Sporting Gijon.
A Betis statement read: "The Real Betis board has this evening decided to dismiss Victor Sanchez del Amo as coach of the first team.
"Real Betis thanks Mr Sanchez del Amo and all his team for their work and wish them the best in their professional futures.
"The board have also decided that the final two games of the current season will be coached by Alexis Trujillo, the club's technical secretary and member of the previous coaching staff."
Victor won seven, drew five and lost 13 of his 25 league matches in charge.