The Siete Leyes (or Seven Laws) were a series of constitutional instruments that fundamentally altered the organizational structure of the young first Mexican republic. They were enacted under President Antonio López de Santa Anna on 15 December 1835 to centralize and strengthen the federal government at a time when the very independence of Mexico was in question.
- The 15 articles of the first law granted citizenship to those who could read and had an annual income of 100 pesos, except for domestic workers, who did not have the right to vote.
- The second law allowed the President to close Congress and suppress the Mexican Supreme Court of Justice of the Nation. Military officers were not allowed to assume this office.
- The 58 articles of the third law established a bicameral Congress of Deputies and Senators, elected by governmental organs. Deputies had four-year terms; Senators were elected for six years.
- The 34 articles of the fourth law specified that the Supreme Court, the Senate of Mexico, and the Meeting of Ministers each nominate three candidates, and the lower house of the legislature would select from those nine candidates the President and Vice-president,
- The fifth law had an 11-member Supreme Court elected in the same manner as the President and Vice-President.
- The 31 articles of the sixth Law replaced the federal republic's "states" with centralized "departments", fashioned after the French model, whose governors and legislators were designated by the President.
- The seventh law prohibited reverting to the pre-reform laws for six years.