Summary: In this article we study a simple random walk on a decorated Galton-Watson tree, obtained from a Galton-Watson tree by replacing each vertex of degree \(n\) with an independent copy of a graph \(G_n\) and gluing the inserted graphs along the tree structure. We assume that there exist constants \(d, R \geq 1\), \(v < \infty\) such that the diameter, effective resistance across and volume of \(G_n\) respectively grow like \(n^{\frac{1}{d}}\), \(n^{\frac{1}{R}}\), \(n^v\) as \(n\to\infty\). We also assume that the underlying Galton-Watson tree is critical with offspring tails \(\xi(x)\) decaying like \(cx^{-\alpha - 1}\) as \(x\to\infty\) for some constant \(c\) and some \(\alpha\in(1, 2)\). We establish the fractal dimension, spectral dimension, walk dimension and simple random walk displacement exponent for the resulting metric space as functions of \(\alpha\), \(d\), \(R\) and \(v\), along with bounds on the fluctuations of these quantities.