In this paper, we introduce a new type of metric spaces called controlled G-metric spaces, denoted, \(G_\zeta \), which are a generalisation of G-metric spaces. This is an extension of the work by Aghajani et al. in the article “Common fixed point of generalised weak contractive mappings in partially ordered \(G_b-\)metric spaces. Filomat 2014, 28, 1087–1101”. We do this by employing a control function \(\zeta (x,y,z)\) to the right-hand side of the \(G_b-\)triangle inequality so that the new triangle inequality becomes \(G_\zeta (x,y,z) \le \zeta (x,a,a)G_\zeta (x,a,a) + \zeta (a,y,z)G_\zeta (a,y,z)\) for all \(a, x,y,z \in X\). Examples of controlled \(G-\)metric spaces which are not \(G_b-\)metric spaces in the sense of Aghajani et al. are given to show that our extension of \(G-\)metric spaces is different. We give some convergence properties on this new space. In order to further illustrate the usefulness of this new structure, a generalised Banach contraction principle is introduced and new fixed point results are developed and proved. Some examples are presented to support main result proved therein. These results improve, unify and generalize already well-known results on \(G-\)metric spaces and \(G_b-\)metric spaces.