The development of effective and eco-friendly cooling technology demands an investigation of new magnetocaloric materials. Compounds containing gadolinium are one of the best candidates due to the large spin-only magnetic moment of Gd 3+ ion. This work reports on the magnetocaloric properties of the AGdS2 family (A = Li, Na, K, Rb) in relation to crystal chemistry of these compounds. These sulfides crystallize in two different structure-types: NaCl (A = Li) and -NaFeO2 (A = Na, K, Rb). Although one would expect the larger magnetocaloric effect to be associated to LiGdS2 due to its higher magnetic/non-magnetic mass ratio, our study demonstrates that the NaGdS2 member leads to the best properties among the investigated series. The change of structure from the 3D NaCl structure of LiGdS2 to the layered -NaFeO2 structure of NaGdS2 drastically improves the magnetocaloric properties.Hence, thanks to its structural features associated to negligible exchange interactions, NaGdS2 exhibits a magnetic entropy change up to 54 J kg -1 K -1 at 2.5 K for µ0H = 5 T, which is comparable to the top ranked inorganic Gd-based materials operating in the cryogenic temperature range. These magnetocaloric figures of merit provide evidence that Gd-based sulfides are promising materials for magnetic refrigeration and, more broadly, this highlights the potential of sulfides in that field.