Abstract: Six neo-clerodane diterpenoids were isolated from the acetone extract of Teucrium quadrifarium Buch-Ham (Ⅰ, Ⅱ, Ⅳ, Ⅴ, Ⅵ and Ⅶ). Five of them (Ⅰ, Ⅱ, Ⅳ, Ⅴ and Ⅶ) were identified as known compounds, teucvidin, 12-epi-teucvidin, teuflin, 19-acetyl-teuspinin and teucvin, respectively. Compound Ⅵ was found to be a new neo-cleredane diterpene, named teuquadrin B. Its structure has been determined from the physical and spectral data.