The invention relates to well bore deflector tools which are used primarily for deflecting tools, lining and the like through a window which has been milled in the side of a well bore casing. A deflector tool (1) is provided with a deflector face (3) at the upper end thereof and means (9, 10) for selectively gripping and releasing a tie back receptacle (8) and/or a well bore casing (6) at a location below the deflector face (3). The gripping means (9, 10) is operable for gripping in response to engagement of the deflector tool (1) with a tie back receptacle (8). Accordingly, the invention provides a simple and automatic means for locking the deflector tool in a required angular position.