Most American women wanting to avoid pregnancy use contraception, yet contraceptive failures are common. Guided by the Health Belief Model (HBM), we conducted a secondary qualitative analysis of interviews with women who described experiencing a contraceptive failure (n = 69) to examine why and how this outcome occurs. We found three primary drivers of contraceptive failures (health literacy and beliefs, partners and relationships, and structural barriers), and we identified pathways through which these drivers led to contraceptive failures that resulted in pregnancy. These findings have implications for how individuals can be better supported to select their preferred contraception during clinical contraceptive discussions.