The blaze at the Pentecostal church on Tottenham High Road broke out at 9:30 on Saturday night.
London Fire Brigade sent six appliances to deal with the incident at Christ Apostolic Church.
Video footage shows smoke billowing onto the nearby street as crews struggled to take control of the blaze.
Transport for London said it had been forced to close a nearby bus lane because of the smoke.
It's not known how the fire started.
A spokesman for the Metropolitan Police said: "Police were called at approximately 9.30pm on Saturday, November 21 to reports of a fire at a church in High Road.
"London Fire Brigade are on scene and are dealing with the blaze."