Claims that women who have elective abortions will experience psychological distress have fueled much of the recent debate on abortion. It has been argued that the emotional sequelae of abortion may not occur until months or years after the event. Despite unclear evidence on such a phenomenon, adverse mental health outcomes of abortion have been used as a rationale for policy-making. We systematically searched for articles focused on the potential association between abortion and long-term mental health outcomes published between January 1, 1989 and August 1, 2008 and reviewed 21 studies that met the inclusion criteria. We rated the study quality based on methodological factors necessary to appropriately explore the research question. Studies were rated as Excellent (no studies), Very Good (4 studies), Fair (8 studies), Poor (8 studies), or Very Poor (1 study). A clear trend emerges from this systematic review: the highest quality studies had findings that were mostly neutral, suggesting few, if any, differences between women who had abortions and their respective comparison groups in terms of mental health sequelae. Conversely, studies with the most flawed methodology found negative mental health sequelae of abortion.