Crews from Hunslet fire station were called to the incident on Acre Road in Middleton shortly after 1am.
A caravan parked in the driveway of a house on the street was well alight when the crews arrived.
The fire had also spread from the caravan to the house as well as a neighbouring property.
Both houses suffered external damage but the fire crews managed to stop the flames taking hold inside.
Families living in the properties were able to escape uninjured.
A spokesman for West Yorkshire Fire and Rescue Service said the cause of the fire was under investigation.