Firefighters were called to family-run Papillon Nursery in Lansdowne Road, just before 11am on Tuesday morning.
Residents in the street watched as the children were led to safety by nursery staff just before the fire brigade arrived.
A spokesperson for Kent Fire and Rescue said they despatched five fire engines following a call at 10.54am, while ‘crews wearing breathing apparatus are using two hose reel jets, a main jet and water from a hydrant’ tackled the fire.
While both the nursery and next door property at the semi-detached building were evacuated, the spokesperson said two adults had been affected by smoke inhalation.
Police were also in attendance, cordoning off the road, while firefighters dealt with the blaze.
The children from the nursery were taken to nearby Rocking Horse Nursery where they waited to be collected by their parents.