Early menopause, the cessation of ovarian function prior to age 45, affects 5-10% of Western women and is associated with an increased risk of adverse health outcomes, including premature mortality and cardiovascular disease. Recent literature suggests that high vegetable protein intake may prolong female reproductive function, but no study has evaluated the association between this exposure and early menopause. Therefore, we evaluated the relationship between cumulative vegetable protein intake as a percentage of total calories and early menopause in the Nurses’ Health Study II cohort. Women included in analyses were premenopausal at baseline (1991) and followed for up to 20 years. Cases (n=2,077) were defined as women experiencing natural menopause before age 45; women were excluded if early menopause was a result of hysterectomy, oophorectomy or radiation treatment. Non-cases were women whose age at menopause was 45 or greater or who were older than 45 and still premenopausal in 2011 (n=51,007). Intake of vegetable and animal protein was assessed every four years via food frequency questionnaires. In Cox proportional hazard models adjusting for age, smoking, diet, and behavioral factors, women in the highest quintile of cumulatively averaged vegetable protein intake (median=6.5%) had a significant 18% lower likelihood of experiencing early menopause as compared to women in the lowest quintile (3.9%) (95% CI: 0.71-0.94; P-trend=0.004). In contrast, animal and total protein was unrelated to risk. Results were similar in analyses limited to never smokers and never oral contraceptive users. Our findings suggest vegetable protein intake may be inversely associated with early menopause.