Sleep Tight (Spanish: Mientras duermes; lit. 'While You Sleep') is a 2011 Spanish psychological thriller film directed by Jaume Balagueró from a screenplay by Alberto Marini which stars Luis Tosar alongside Marta Etura. In the film, César (Tosar), a concierge of an apartment building, is unable to reach happiness no matter what happens to him, and he has a goal to make the tenants upset. Clara (Etura) proves to César that making her upset is harder than he expected and things turn to a twisted event when her boyfriend Marcos visits her. Sleep Tight was among the most anticipated films to premiere at the 44th Sitges Film Festival.