Mexico’s first Penal Code (published in 1871) which entered into force in 1872, made no reference to the criminalisation of sodomy or any other consensual same-sex act between adults.

Nevertheless, LGBTQ people could be prosecuted under the vague language of article 787 (Third Book; Title 6 'Violations against family order, public decency, or traditional customs'; chapter II 'Offences against public morals or good manners'), which never mentioned any sexual orientation or gender identity. The penalty included arrest and a fine if the alleged 'indecent act' was committed either in a public place (with or without witnesses) or in a private place.

The first known reference of the application of this article towards LGBTQ people dates from November 1901 when the scandal of the 'baile de los cuarenta y uno' (the 'Ball of the Forty-One') occurred. Police illegally raid a private home in Mexico City where 41 men (some of them dressed in women's clothing) from the upper classes of the Mexican society were attending an event. The identity of the suspects was never disclosed, but according to some sources, there are some press articles at the time that state some of them could be conscripted into the army and sent to Yucatán to public works. This was as the Caste War against the Mayan Indigenous rebels was finalising. There are seven names listed in the records of the Supreme Court who filed a writ of protection against their conscription to the army because homosexuality was not illegal in Mexico at the time. Hence, the charge was simply replaced (crime against decency), but the punishment didn't change.

This Penal Code was replaced in 1929.

From the 1600s to the short Second French intervention and the subsequent restoration of the Republic under President Juárez, sodomy was heavily criminalized in Mexico. The medieval laws issued in the Kingdom of Castile were still valid for all the territories of the Hispanic Monarchy in the Americas. These laws still heavily criminalised acts of sodomy and were still part of the chaotic Mexican legal body even after achieving independence.
In the first half of the 19th century, Mexico experienced political instability and a series of civil wars and revolts. All the efforts to enact a solid, unified legal body for this new country were unsuccessful until the 1870s.

In the 2000s, some states had codes banning same-sex marriages while others either didn’t recognise them without a ban or provided for civil unions.

In 2010, Mexico City became the first part of Mexico to recognise same-sex marriage. Other states would follow suit until the end of 2022, when all states would recognise same-sex marriage in Mexico.

In 1966, Article 201 of the Federal Penal Code mentioned homosexuality as an "immoral practice" that was discouraged to encourage to minors. Other states would also implement similar laws until the repeal in 1998.

LGBTIQ+ people faced heavy persecution in Mexico during the Spanish Inquisition.

When Mexico decriminalised homosexuality in 1872, there were still vague references that persecuted LGBTIQ+ people in practice in Article 787 against "violations against family order, public decency or traditional customs". The most notable case of this was in 1901 when 41 crossdressers were raided by the police in a private home.

Until 2004, there was no legal gender recognition in Mexico.

On February 11th, 2022, Fausto Martínez became the first person in Mexico to receive a non-binary gender marker on their birth certificate. The marker was issued by the Civil Registry of Guanajuato.

Before February 11th, 2022, no non-binary person had ever been issued a non-binary gender marker in Mexico.

Since 1917, Article 1 of the Political Constitution of the United Mexican States has prohibited discrimination on any grounds. However, the explicit mention of sexual orientation as a basis for discrimination was only added during the 2011 reform of this article. Since then, it has also established that all Mexican authorities, within their respective jurisdictions, are obligated to promote, respect, protect, and guarantee human rights, in accordance with the principles of universality, interdependence, indivisibility, and progressiveness. Consequently, the Mexican State must prevent, investigate, sanction, and remedy human rights violations. Provisions related to human rights must be interpreted in accordance with the Constitution and international treaties, always favouring the broadest protection for individuals.

Before this, in 2003, the Federal Law to Prevent and Eliminate Discrimination was enacted, marking the first legal tool requiring the Mexican State to create the conditions necessary for the real and effective equality of individuals. As a result, federal authorities must take action, both independently and collaboratively, to remove obstacles that hinder or prevent the full development of individuals and ensure that everyone enjoys the rights and freedoms guaranteed by the Political Constitution of the United Mexican States and by international treaties to which Mexico is a party. And thus, Article 4 (now Article 1, section III after the 2014 reform) of this law explicitly includes sexual orientation as one of the grounds for negative discrimination.

Some regions have also began providing protections on the basis of gender identity, starting with Mexico City in 2014.

Most of Mexico's states have enacted laws that ban discrimination based on sexual orientation or sexual preference, as well as gender. Many states also explicitly ban discrimination based on gender identity in local laws.

No laws seek to identify or prevent the enrollment of gays in Mexico’s armed services. However, a high prevalence of harassment, encouraged leave, and dishonorable discharge was often issued if one was interpreted as homosexual until 2012.

In 1994, Mexico passed a policy on blood donation under NOM 003-SSA2 which explicitly banned gay and bisexual men from donating blood. The ban would be repealed in 2012.

Until 1994, there was no known policy or law restricting or banning blood donations from men who have sex with men in Mexico.

Mexico City was the first region within Mexico to ban conversion therapy. Here is a list in chronological order showing every region that has banned the practice:
- Mexico City (2020)
- State of Mexico (2020)
- Oaxaca (2021)
- Baja California Sur (2021)
- Zacatecas (2021)
- Yucatán (2021)
- Tlaxcala (2021)
- Colima (2021)
- Jalisco (2022)
- Baja California (2022)
- Hidalgo (2022)
- Sonora (2022)
- Nuevo León (2022)
- Puebla (2023)
- Querétaro (2023)
- Sinaloa (2023)
- Morelos (2023)
- Quintana Roo (2023)
- Guerrero (2024)

Before Mexico City’s ban, no federal entity in Mexico outlawed conversion therapy.