Eight new <i>neo</i>-clerodane diterpenoids (<b>1</b>-<b>8</b>) were acquired from the aerial parts of <i>Ajuga pantantha</i>. Spectroscopic data analysis permitted the definition of their structures, and experimental and calculated electronic circular dichroism data were used to define their absolute configurations. Compounds <b>2</b> and <b>4</b>-<b>8</b> were found to have NO inhibitory effects with IC₅₀ values of 20.2, 45.5, 34.0, 27.0, 45.0, and 25.8 μM, respectively. The more potent compounds <b>2</b>, <b>6</b>, and <b>8</b> were analyzed to establish their anti-inflammatory mechanism, including regulation of the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins as well as their binding interactions with the two proteins.