Rotary knob or handle 1 for opening and/or closing doors, gates or windows, comprising a first part 2 designed to operate a closing mechanism by rotation around a rotation axis X, a second part 3 which is rotatable around substantially the same axis X, a connecting part 5, which is coupled to said second part 3 in rotation around said axis X. The connecting part 5 is movable with respect to the first part 2 along said axis X, between a first position and a second position. In said first position of the connecting part 5, the connecting part 5, and with it the second part 3, are substantially freely rotatable around said axis X with respect to said first part 2. In said second position of the connecting part 5, the connecting part 5 and the second part 3 are rotationally coupled by a dog clutch to said first part 2. The rotary knob or handle 1 is provided with several push buttons 4 on said second part 3, arranged at an angle with respect to said rotation axis X. Any one of said at least two push buttons, when pushed, displaces said connecting part 5 from said first position towards said second position, closing the dog clutch and enabling the operation of the closing mechanism through rotation of the second part 3.