It is generally accepted that education is a powerful enabler of social mobility in the modern world. However, access to quality and specialized education is still highly unequal, creating pathways for some groups of people and barriers to others. This dissertation explores three approaches to understanding and addressing inequalities of opportunity in three separate chapters. The first chapter examines the importance of test design, in particular the time limit component, as a driver of gender gaps in performance. The second chapter evaluates the potential of a growth mindset intervention for narrowing gender gaps in challenge-seeking and competitive behavior. The third chapter investigates the educational attainment and labor market outcomes of an affirmative action policy for college admission that targets low-income and underrepresented racial minorities. Respective results show that changing the time limit of a test may increase female representation in competitive programs, teaching growth mindset may help some women become more challenge-seeking and competitive, and that affirmative action can more than double the chances of black low-income students entering a prestigious career without negatively impacting the prospects of students displaced by the policy. In summary, these studies provide evidence that inform the potential of an institution, a practice, and a policy to open pathways for more equitable opportunities in education and the labor market. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]