UN Declaration of Human Rights, Article 18

Everyone has the right to freedom of thought, conscience and religion; this right includes freedom to change his religion or belief, and freedom, either alone or in community with others and in public or private, to manifest his religion or belief in teaching, practice, worship and observance. 

OAS American Convention on Human Rights, Article 12. Freedom of Conscience and Religion

1. Everyone has the right to freedom of conscience and of religion. This right includes freedom to maintain or to change one's religion or beliefs, and freedom to profess or disseminate one's religion or beliefs, either individually or together with others, in public or in private.

2. No one shall be subject to restrictions that might impair his freedom to maintain or to change his religion or beliefs.

3. Freedom to manifest one's religion and beliefs may be subject only to the limitations prescribed by law that are necessary to protect public safety, order, health, or morals, or the rights or freedoms of others.

4. Parents or guardians, as the case may be, have the right to provide for the religious and moral education of their children or wards that is in accord with their own convictions.

US Bill of Rights, 1st Ammendmemt to the Constitution

Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.

Canadian Charter of Rights & Freedoms, Section 2:A-D, Fundamentalist Freedoms 

Everyone has the following fundamental freedoms:

(a) freedom of conscience and religion;

(b) freedom of thought, belief, opinion and expression, including freedom of the press and other media of communication;

(c) freedom of peaceful assembly; and

(d) freedom of association.

Mexican Constitution, Article 24

[Pending translation verification]