While commonly-used pastels or blues may be suitable for the room of a young boy, as your child gets older, a teenager will want to start establishing his own identity and feeling more like an adult. It can be difficult to decide what is suitable for a teenager as he may want a style for his room that is radically different from what he had as a child. While he will have his own ideas, there are a few colors and color combinations that will appeal to the tastes of many teenage boys. A plain gray can be a very masculine color for a room, which your teenage boy is sure to appreciate. This is a particularly good color for minimalist or contemporary styles, which are also well-suited for a more masculine decor.