West Yorkshire Fire and Rescue Service said 12 fire engines were called to the scene of the fire on land near Cullingworth, to the north west of Bradford.
A spokesman said: "Appliances from across the area are in attendance, with over 50 firefighters dealing with the incident under extreme heat conditions."
He said a police helicopter was assisting the firefighters by identifying hotspots on the moor.
The fire is at a location called Catstones Moor and Keighley Road and Ryecroft Road are currently closed. It was reported on Sunday just after 3pm.
Nearby residents have been advised to keep their doors and windows closed.
Bradford Council said: "The latest news we have on the Cullingworth Moor fire is that it is being controlled by emergency services and that smoke is blowing away from homes. If you do smell smoke, please stay indoors and close windows."
Air passengers reported on social media being able to see the smoke from the moor fire as they approached Leeds Bradford Airport.
The blaze follows the huge blaze on Saddleworth Moor, which saw troops being brought-in to help firefighters, and another massive moor fire at Winter Hill, near Bolto