Texas is, of course, known for its gun-friendly laws. The state does not require a permit or registration to own or purchase a gun. A permit is required for carrying a handgun but Texas is a shall-issue state which means that they are required to issue a permit to any qualified applicant. Texas has castle doctrine and stand-your-ground laws which allow a person to use deadly force against anyone forcibly and unlawfully entering or attempting to enter their home. The person using self-defense does not have a duty to retreat.