The fire broke out in the bathroom of the house on Gibraltar Avenue, Halifax.
Fire crews from Halifax and Illingworth were at the scene within minutes of the call, which was made at 3.08am.
A spokesman said two adults and four children were all taken to hospital suffering from the effects of smoke inhalation, adding one adult had suffered burns to their hands as a result of tackling the fire.
It is understood the fire started after a candle was left burning in the bathroom. A fire service spokesman said there were also no smoke alarms fitted in the property.