Spanish second-tier side Almeria announced Guti's arrival in a series of tweets after the departure of Pedro Emanuel.
It is Guti's first senior coaching role, having previously coached Madrid's youth team and served as an assistant at Turkish giants Besiktas.
Guti joins Almeria, who are second in the Segunda table but 10 points adrift of leaders Cadiz after 14 rounds in the race for LaLiga promotion.
Almeria – who last featured in LaLiga in 2014-15 – have only lost twice this season and are five games unbeaten.
The 43-year-old Guti's first match in charge will be against fifth-placed Real Zaragoza on Sunday.