Saraphia siamensis gen. nov. & sp. nov. (Acari: Eriophyoidea) from Mammea siamensis (Miq.) T. Anderson in Thailand is described, illustrated. We provide a geometric morphometric analysis based on different geoghraphic populations. Additionally, we report Vasates spondiasi Boczek & Chandrapatya, 1989, a new record from M. siamensis. No visible damaging symptom was observed for both eriophyoid mite species, indicating that they are vagrants on the underside of leaves.