Olive cultivar classification has been a primary concern for olive growers since the earliest times of olive cultivation. As one of the earliest fruit crops to be domesticated, the number of olive genotypes cultivated in the Mediterranean region and elsewhere is high, and the assessment of an easy and undisputed system of classification has become increasingly urgent. This is also because of the high number of synonyms and homonyms in existence. The present review examines the history of attempts, in all olive-producing countries and by many researchers, to achieve an ultimate and exhaustive descriptor list that is valid for all past, present and future genotypes, to support technicians, growers and scholars. After a thorough review of the numerous elaiographical lists proposed, the modern research tools that have been applied to olive (i.e., ultrastructural, biochemical, DNA and molecular markers) are examined critically. A balance sheet has been prepared, taking into account initiatives by major international and national institutions.