This is a complicated question. Legally, in the United States, there is no religious "test" for marriage - any one person of any faith may choose to marry any other person of any faith provided certain requirements about age, degree of consanguinity, gender (in some states) and consent are met. In most developed countries, the above holds true. In developing and undeveloped countries, there may be national laws prohibiting interfaith marriages - you would need to check with the individual country.In terms of religion, this will vary by faith - some denominations refuse to offer the blessing of marriage on interfaith couples while other denominations accept the differing faiths. A few denominations and several religions (Greek Orthodox, orthodoz Judaism and Catholicism come to mind) typical