In this paper, we investigate the stability of the following general septic functional equation: \(\sum_{i=0}^8{ }_8 C_i(-1)^{8-i} f(x+(i-4) y)=0\)which is a generalization of many functional equations such as the additive functional equation, the quadratic functional equation, the cubic functional equation, the quartic functional equation, the quintic functional equation, and the sextic functional equation. The equation is analysed from the perspective of Hyers-Ulam-Rassias stability.