Franciscus "Frank" de Boer (Dutch pronunciation: ; born 15 May 1970) is a Dutch football manager who is currently the head coach of Atlanta United. A former defender, De Boer spent most of his professional playing career with Ajax, winning five Eredivisie titles, two KNVB Cups, one UEFA Cup and one UEFA Champions League. He later spent five years at Barcelona, where he won the 1998–99 La Liga title, before retiring after short spells at Galatasaray, Rangers, Al-Rayyan and Al-Shamal.
De Boer is the second most capped outfield player in the history of the Netherlands national team, with 112 caps. He captained the Oranje to the semi-finals of both the 1998 FIFA World Cup and UEFA Euro 2000. He is the twin brother of Ronald de Boer, with whom he was a teammate at Ajax, Barcelona, Rangers, Al-Rayyan, Al-Shamal and the Netherlands national team.
After retiring from playing, De Boer went into management with the Ajax youth team and as assistant to Bert van Marwijk with the Netherlands national team. In December 2010, he took over as manager of Ajax and went on to win the Eredivisie title in his first season. In 2013, he received the Rinus Michels Award for manager of the year in the Netherlands after leading Ajax to their third successive Eredivisie title. The following year, he became the first manager to win four consecutive Eredivisie titles. He then had brief spells managing in Serie A with Internazionale in 2016 and Crystal Palace in the Premier League in 2017.