A lens position adjustment system (10) permits adjustment of the position of a projection lens (5) relative to a projector (100) for making a Scheimpflug adjustment. The projection lens (5) has an optical axis (6). The system (10) comprises: a first support part (20) for fitting to, or forming part of, the projector (100); a second support part (40) for fitting to, or forming part of, the projection lens (5); and a connecting part (30). The connecting part (30) is pivotally connected to the first support part (20) and pivotally connected to the second support part (40) and configured to permit independent adjustment of the second support part (40) relative to the first support part (20) about two axes of rotation (7, 8) which intersect, and are perpendicular to, the optical axis (6) of the projection lens (5). A locking mechanism (28, 29, 51-58) is provided for securing a position of the second support part (40) relative to the first support part (20).