Texas bigamy laws prevent the act of marrying someone while already married to someone else. As of 2014, bigamy is not only illegal in Texas, but it is also against the law in every state of the United States and is punishable by a penalty of up to 5 years in prison.
Although the Mormon religion originally permitted polygamy, which is the practice of having more than one wife, the U.S. Supreme Court ruled in 1878 that having more than one wife was a violation of criminal law and that practicing polygamy was not an exercise in religious liberty. Notably, polygamy is legal in some countries, including Somalia, Saudi Arabia and South Africa.
Under the Texas Penal Code Section 25.01, a person is guilty of bigamy when he is legally married and purports to marry or marries someone other than his spouse, lives with a person other than his spouse under the appearance of being married or knows that a married person other than his spouse is married and purports to marry that person. The offense is a third-degree felony under most conditions, but can be enhanced to first degree felony status if the person with whom the person commits bigamy with is under the age of 16.