Twenty-five years after the Revised European American Classification of Lymphoid Neoplasms classification was published, its principle of an integrative approach to disease definition based on several parameters still prevails and has been adopted and expanded in the following World Health Organization classifications of tumors of the hematopoietic organs. The latest World Health Organization classification revised in 2017 comprises more than 80 entities of mature lymphoid neoplasms (B-cell, T-cell, and Hodgkin lymphomas), which are defined according to their morphology, immunophenotype, genetic lesions and molecular profiles, clinical features, and cellular derivation. The classification also recognizes both incipient and indolent lymphoid neoplasms with a low potential of progression. In this review, we highlight some of the new data and recent modifications introduced in the 2017 classification.