This paper provides a full taxonomic revision of the genus Oxalis for the flora of Egypt. The study was carried out on herbarium specimens as well as fresh materials. The study revealed the presence of five species and one variety belonging to three sections by adding O. corymbosa and O. latifolia. Oxalis corniculata is a polymorphic taxon in Egypt which led to the recognition of O. corniculata L. with its type var. corniculata and O. corniculata L. var. repens (Thunb.) Zucc. The species are mostly weed of cultivation along Mediterranean and Nile Valley with the exception of O. anthelmintica which is restricted to southeastern corner of Egypt. Among the studied taxa, variation in the presence or absence of stem, bulb characters, leaflets shape and color of flowers were found significant diagnostic characters for delimiting the taxa. For each taxon, update nomenclature, synonyms, type, amended descriptions, distribution (local and global), representative specimens are given. Photographs and diagnostic key to the species are provided to assist in identification.