Johannes Juul (27 October 1887 – 5 November 1969) was a Danish engineer who is remembered for the important part he played in the development of wind turbines.

When he was 17, he became a student at Askov Højskole, a folk high school, where he was one of the first to study wind electricity applications under the pioneer Poul la Cour.

In order to save power and reduce risk, he created a model with hotplates operating at 6, 11 and 14 volts, depending on the amount of heat required.

After much experimentation with wind tunnels, the first turbine with two blades and producing 10 kW, was developed in 1950 and installed at Vester Egesborg in the south of Zealand.

Now dismantled, its essentials can be seen at the Energy Museum (Energimuseet) near Bjerringbro in central Jutland,[3] while the tower still stands near the east coast, 2 km North of Gedser.

Juul's visionary conclusions in 1962 turned out to be confirmed by subsequent progress in the Danish wind industry which 40 years later had become the greatest supplier of turbines to the world market.