Good Friday's dramatic draw against Rotherham means the Cobblers are four points ahead of relegation rivals Barnet ahead of the Bees trip to Priestfield.
Gillingham currently occupy the final play-off place so will be giving the game their all.
An excellent crowd of 5,167 saw a game of two halves at Sixfields but would have been heartened by the spirit shown by Gary Johnson's men as they battled back from two goals down to earn a crucial point.