Laura Jubb, of Halton Moor, Leeds, had put a pan of eggs on to boil in her kitchen and fallen asleep at about 11.30pm yesterday (August 8).
An alarm started to sound as the house began to fill with smoke but the family did not hear it.
Luckily, next-door neighbour Alvidas Dauksys, 39, heard the alarm and used a spare key to open the door and rescue the family.
Ms Jubb said: “I put the eggs on to boil at about half-past 11, then I fell asleep.
“The next thing I knew, my next-door neighbour was waking me up and carrying the kids out. It was about quarter past two.”
Mr Dauksys, known as Elvis to his friends, said: “It was 2am and a fire alarm woke me up. I looked out of the window and I saw smoke coming out.
“We called the ambulance and fire brigade and I rushed to get into the house.
“They were all asleep, even though the alarm was very loud.
“The fire was going downstairs in the kitchen. There was a lot of smoke.
“Luckily, I had a key which my neighbour gave me in case she lost hers.
“I was lucky to be able to get in there quickly. I woke them up and brought them down.”
Ms Jubb, 25, said she felt very fortunate that she, daughter Stella, eight, and sons JJ, seven, and Daniel, five, were all safe and well.
She said they owed Mr Dauksys their lives.
She said: “I’m going to buy him a big bunch of flowers and a crate of Budweiser.
“I’m really lucky to be here. I don’t know how none of us woke up.
“I would have been dead without him.”
A spokesperson for West Yorkshire Fire and Rescue service said two fire engines from Killingbeck Fire Station and one from Leeds had been called to the scene but the pan fire was out on their arrival.
The spokesperson said: “Firefighters ventilated the area. No one has been hurt.”
Ms Jubb and her children were checked over for smoke inhalation by paramedics at the scene but were all unharmed.
The house was left smoke-damaged and the cooker had to be disconnected, Ms Jubb said.
Firefighters have now fitted an extra smoke alarm in her bedroom, she said.