A systematic study of 16 taxa belonging to 14 species of Ardisiasubgenus Crispardisia distributed in Thailand was conducted by means of numerical analysis on 13 morphological characters, including vegetative and floral characters. Based on UPGMA clustering and PCA, calyx length is the most important character and three main groups are recognised by multivariate analysis of morphological characters. The result of this study and literature review recommends that A. crenata Sims subsp. obtusifolia Chatan & Promprom mustbe placed under A. crenata Sims. Ardisiacrenata Sims var. angusta C. B. Clarke and A. symplocifolia (C. Chen) K. Larsen & C. M. Hu are new synonyms of A. crispa (Thunb.) A.DC. and A. maculosa Mez, respectively.