An electronically controlled butterfly valve comprising a valve body, a valve seat formed in the valve body, a butterfly disc adapted to engage the valve seat, a shaft on which the butterfly disc is keyed, an electric motor coupled to the shaft by means of a gear transmission having a final gear keyed on the shaft, a spiral return spring adapted to rotate the butterfly disc towards the closed position, and an opposing spring adapted to rotate the butterfly disc towards a limp-home position defined by an abutment body against the action of the return spring; the opposing spring is a flat leaf spring and is mounted on a moving member which is mounted coaxially and idly on the shaft and has a projection adapted to engage in abutment against the abutment body, an end of the opposing spring being free and ending in a projection which is disposed so as to be superimposed on the trajectory followed by a member rigid with the final gear.