We investigate weighted Sobolev spaces on metric measure spaces (X, d, m). Denoting by ρ the weight function, we compare the space W 1,p (X, d, ρm) (which always concides with the closure H 1,p (X, d, ρm) of Lipschitz functions) with the weighted Sobolev spaces W 1,p ρ (X, d, m) and H 1,p ρ (X, d, m) defined as in the Euclidean theory of weighted Sobolev spaces. Under mild assumptions on the metric measure structure and on the weight we show that W 1,p (X, d, ρm) = H 1,p ρ (X, d, m). We also adapt the results in [22] and in the recent paper [26] to the metric measure setting, considering appropriate conditions on ρ that ensure the equality W 1,p ρ (X, d, m) = H 1,p ρ (X, d, m).