The genus Euphorbia is the largest in Saudi Arabia, even though no anatomical study has been done intensively. In this study the epidermis, the stomata and the venation patterns have been investigated. The shape of the epidermal cell in Euphorbia species in Saudi Arabia varies: polygonal, rectangular, undulate or elongated. Moreover, the cell shape relies on the cell location on a leaf, i.e. the middle region, the margin, the apex or above the vein. Furthermore, in some cases both leaf surfaces have the same cell shape but more often they are unlike. Hairs are generally simple, unbranched and with a warty ornamentation on their surface. Papillae occur only in one species E. hypericifolia .The most common stomata type is anomocytic, while the rare type is actinocytic, recorded only in E. helioscopia. Stomata of more than one type (have been encountered on the same leaf surface as in E. scordiifolia and E. hirta. Venation patterns vary from one-veined, three-veined to those with four or more veins.