As international agricultural markets become increasingly more integrated, internationally harmonized farm classification systems could become more useful for international comparisons of agricultural industries, as a tool for summarizing and analyzing micro-level data. Canada, Mexico, and the United States currently do not have a common farm classification system beyond the harmonized North American Industrial Classification System (NAICS), which the three countries developed and adopted shortly after the implementation of the North American Free Trade Agreement (NAFTA). While common policy themes exist among the three countries, such as competitiveness, innovation and sustainability, they have yet to be reflected in a comprehensive farm classification system. This paper compares farm structures in North America, using the NAICS and farm size. Additional classifications that are used in North America are summarized. Additional farm characteristics that could enhance the comprehensiveness of farm classification systems are discussed. Finally, data constraints which limit the ability to develop a harmonized classification system in the three jurisdictions are discussed.