Recent studies have linked personality with family formation and having children. We studied whether personality traits are differentially associated with planned versus non-planned pregnancies. The participants were 8336 men and women from the 1958 British birth cohort study, with personality assessed in adulthood using the Five Factor Model. Planned pregnancies were more likely in women with high agreeableness and low openness to experience, and in men with high extraversion, high emotional stability, high conscientiousness, and low openness to experience. Non-planned pregnancies were more likely in women with high extraversion, low emotional stability, and low conscientiousness, and in men with high extraversion and low agreeableness. These results indicate that personality is associated with fertility differences via different pathways of fertility planning.