The isolation of the CHCl3 soluble extract of Kaempferia pulchra rhizomes afforded seven new isopimarane diterpenoids, kaempulchraols I−O, together with one known analogue. The structures of these compounds were elucidated using 1D and 2D NMR and X-ray diffraction analyses. The antiproliferative activity of the isolated compounds was evaluated against a panel of five human cancer cell lines. Kaempulchraol L exhibited weak antiproliferative activity against PANC-1 and PSN-1 cells with IC50 values of 39.9 and 22.6 μM, respectively.