Some consider every game in the entire Grand Theft Auto series to be Three-Dimensional (3D). This means that 3D models are used, and the camera/view would be able to move around them fully; as opposed to Two Dimensional (2D) where the camera view is heavily limited.
However most people consider GTA, GTA 2 and GTA Advance to be 2D. The top-down perspective looks to be 2D, and many aspects of the game are (including the vehicles and pedestrians). On the other hand the player can clearly see the sides of the buildings when going around them, which are drawn on-the-fly from 3D models.