1930
- The National Revolutionary Party (PNR), the predecessor to the Institutional Revolutionary Party (PRI), is founded.
- President Emilio Portes Gil is elected.
- Mexico joins the League of Nations.
1931
- The Mexican government begins construction of the Palace of Fine Arts in Mexico City.
1932
- President Abelardo L. Rodríguez is elected.
- The Cristero War, a religious conflict between the Mexican government and conservative Roman Catholics, ends.
1933
- President Lázaro Cárdenas is elected.
- The Mexican government begins a program of land reform, distributing millions of acres of land to peasants.
- The Mexican government also begins a program of nationalization, taking control of foreign-owned oil companies and railroads.
1934
- Mexico hosts the FIFA World Cup.
1935
- The Mexican government passes the Federal Labor Law, which establishes workers' rights and protections.
1936
- President Cárdenas expropriates the remaining foreign-owned oil companies in Mexico.
- Mexico becomes a founding member of the United Nations.
1937
- The National Polytechnic Institute is founded in Mexico City.
- The Mexican government passes the Agrarian Code, which establishes the legal framework for land reform.
1938
- President Manuel Ávila Camacho is elected.
- Mexico enters World War II on the side of the Allies.
1939
- The Mexican government passes the Social Security Law, which establishes a social security system for workers.