The harderian gland is a compound tubuloacinar gland located around the posterior aspect of the eye ball in the majority of land vertebrates. Despite this gland has been comprehensively studied in several mammalian species, little studies tackled the lagomorph’s harderian gland. The present study was undertaken to describe the structure of the rabbit (Oryctolagus cuniculus) harderian gland and to evaluate effects of atropine sulphate (As; muscarinic antagonist) and neostigmine (NS; muscarinic agonist) on the physiology and ultrastructure of the gland. The gland was found to be composed of two lobes; a dorsal white and larger ventral pink lobes. Treatment of animals with As did not affect total lipid contents,decreased total protein contents and increased acid phosphatase activities in both lobes. In addition, treatment with As induced mitochondrial degeneration and cytoplasmic vacuolization in the secretory epithelial cells of the white lobe. In the pink lobe, As treatment inhibited release of lipid from the secretory epithelium and induced partial contraction of myoepithelial cells. Treatment of animals with ns increased total lipid content, only in the pink lobe, decreased total protein contents and increased phosphatase activities in both lobes. NS induced too notable accumulation of lipid vacuoles at the apical part of the secretory epithelial cells, appearance of mitochondria with signs of degeneration and loss of internal structures and partial contraction of myoepithelial cells in the white lobe. In case of the pink lobe, ns induced appearance of degenerative signs in the mitochondria and vacuolization of the cytoplasm in the epithelial cells and contraction of myoepitelial cells.