Chapter 3 describes the principle of primacy of reality in Latin America, namely, in Argentina, Brazil, Chile, and Uruguay. The principle is also contained in the International Labor Organization’s Recommendation 198. The principle posits that facts must be given preference over what parties, particularly employers, state in legal texts, documents, and agreements. It is particularly important when determining threshold questions in labor law, such as employee and employer status. While employers might deny an employment relationship given a formal agreement to hire workers as independent contractors, the facts might show otherwise. However, the chapter also argues that primacy of reality depends on the principle of protection and in dubio pro operario to resolve questions when the facts are not dispositive given vague or missing rules. The chapter then searches primacy of reality in the United States and finds it in various employment tests, such as the common law control test. It is also finds it in employer tests of joint employer status. However, many of those tests remain vague, requiring supplementation with the U.S. versions of in dubio pro operario, i.e., liberal construction of the statutes that derogate the common law, and with legislative purpose. Primacy of reality makes it even more important for legal operators to be cognizant of labor law principles and, principally, the protective principle.