In this study, monophasic strontium and barium stannate (SrSnO3, Sr2SnO4, BaSnO3, Ba2SnO4) powders were synthesized by means of environmentally friendly aqueous sol–gel technique under neutral conditions. However, it was established that the successful sol–gel synthesis of appropriate calcium stannates (CaSnO3 and Ca2SnO4) can be performed only at acidic sol–gel processing conditions. Moreover, the influence of nature of alkaline earth metal source on the phase purity of different metal stannates was evaluated. The thermal behaviour of Ca–Sn–O, Sr–Sn–O and Ba–Sn–O precursor gels was investigated by TG-DSC measurements. The phase purity, crystallization peculiarities and microstructural evolution of the sol–gel derived alkaline earth metal stannate powders were studied by XRD and SEM measurements.