Phytochemical investigation on the anti‐inflammatory fraction extracted from the whole plant of Euphorbia helioscopia L. led to the isolation of three new ent‐atisane diterpenoids (1–3) and five known analogues (4–8). The structures and absolute configurations of the new compounds were elucidated by comprehensive analysis of the NMR, MS, IR, ECD, and X‐ray crystallography. It is worth mentioning that compound 3 belongs to a rare class of ent‐atisane diterpenoid featuring a hydroxyl group at C‐9. Bioactivity investigation showed that compounds 4, 7, and 8 exhibited significant inhibitory effects on LPS‐induced NO production in a dose‐dependent manner, which indicates their anti‐inflammatory potential.