An electrical bushing having an anti-rotation mounting flange for preventing rotation of a body element of the electrical bushing is provided. The electrical bushing includes a mounting flange, at least one locking element and a body element having a circumferential protrusion. At least one first recess is formed in the circumferential protrusion, and the at least one locking element is configured to engage with the at least one first recess and with the mounting flange for restricting relative rotation of the body element relative to the mounting flange about a longitudinal axis R. A further aspect provides an electrical transformer including at least one electrical bushing according to the above. A yet further aspect provides a method for mounting the electrical bushing according to the above.