Yes, it is. The movie 'The Room' has roots in a true story. Tommy Wiseau, the creative force behind it, has said that parts of his own life are reflected in the film. For example, the complex relationships between the characters might mirror some of his personal relationships. But the movie also has a lot of elements that seem very much like artistic license, so it's hard to tell exactly where the truth ends and the fictionalization begins. It has become a cult classic precisely because of this blend of the real and the absurd.
In fact, 'Room' has roots in a true occurrence. The filmmakers took elements from a real story and transformed them into this compelling narrative. However, some creative liberties might have been taken to make it more cinematic.