This national study used the Delphi method to identify perceived barriers women face in the pursuit of STEM careers. The study used a series of three web-based questionnaires. The first round of the study used a questionnaire with an open-ended question to facilitate the generation of a wide array of response categories. In round two, respondents were asked to rate the 24 perceived barriers from round one on a Likert-type scale and to make changes as necessary. In round three, respondents were asked to provide a dichotomous indication of whether they agreed or disagreed with each of the items. Consensus on 22 perceived barriers was reached after three rounds. The major barriers identified by the respondents were: male domination of STEM careers, lack of awareness of educational and career opportunities, STEM education and toys directed at boys, a lack of female mentors/role models, minimization of barriers, personal expectations, the time required to become proficient in a STEM field, lack of encouragement from men, and the perceived glass ceiling of women in STEM careers. It is recommended that future research focus on the efficacy of formal, informal, and non-formal education models toward increasing awareness of educational and career opportunities in STEM. Researching effective methods to recruit and retain females in STEM degree programs is also suggested.