West Yorkshire Fire and Rescue Service said that large areas of Moorland caught fire on Saturday afternoon.
More than 50 acres of Moorland was ablaze at one point yesterday, with fire crews from North Yorkshire Fire service drafted in to help dampen down the flames.
Crews from 10 engines remained at the scene of the blaze overnight to damp down.
Bradford Council has warned people to stay away from the Moor.
Ilkley residents said the fire spread quickly across the hillside after a day of hot sunshine.
North Yorkshire Fire and Rescue Service watch manager Martyn Hughes, tweeted: "The intense heat, steep slopes and rough terrain are causing the fire to spread rapidly whilst we try to get near the flames."
And the hot weather is set to continue for the rest of the Easter weekend.