A phytochemical investigation of the stem barks of the Malaysian Croton oblongus Burm.f. (Syn. Croton laevifoliusBlume) (Euphorbiaceae) yielded seven previously undescribed ent-neo-clerodane diterpenoids, laevifins A - Gand the known crovatin (3). Structures were established by a combination of spectroscopic methods includingHRESIMS, NMR spectroscopy and X-ray crystallography. The absolute configuration of crovatin and laevifins AGwas established by comparison of experimental ECD and theoretical TDDFT ECD calculated spectra. This is thefirst report on the occurrence of the sesquiterpenoid cryptomeridiol in a Croton species. In vitro cytotoxicityassays on laevifins A, B and G showed moderate activities against the MCF-7 cancer cell line (IC50 102, 115 and106 μM, respectively) while β-amyrin and acetyl aleuritolic acid showed good anti-inflammatory activity on theLPS-induced NF-κB translocation inhibition in RAW 264.7 cells assay with IC50 values of 23.5 and 35.4 μg/mL,respectively.