In order to file for an annulment, a party must establish the underlying marriage was either void or voidable. Under 23 Pa C.S. 3304, void marriages include those where (1) one of the spouses is still in a former marriage, (2) the parties are too closely related, (3) either of the parties was incapable of consenting to the marriage, usually due to mental disorder, or (4) either of the parties was under 18 if claiming a common law marriage. A void marriage is one that is invalid because it violates some public policy.

Under 23 Pa C.S. 3305 grounds for voidable marriage include: (1) where either party is under 16 without court approval, (2) where either party is 16 or 17 without court approval or parental consent, (3) where either party was under the influence of alcohol or drugs at the time of the ceremony impacting their ability to consent, (4) either of the parties is incurably impotent, or (5) there was fraud, duress, coercion or force to secure the marriage. A voidable marriage is presumptively valid unless a party challenges it. There is a sixty day time limit to pursue an annulment from the ceremony date for several of the voidable grounds. Additionally, regarding void and voidable marriages, the right to annulment is lost if there is subsequent confirmation of the marriage after becoming aware of the potential grounds for annulment. Where an annulment is to be granted, equitable distribution and potential support claims may proceed just as in a divorce action.