The relationships between dietary components and physical or hormonal sexual maturation in 63 pubertal girls were examined. The effects of vegetable protein and dietary fiber on breast development (B = -2.0, P < 0.05; B = -2.6, P < 0.05, respectively) and menarche (B = -3.3, P < 0.05; B = -2.6, P < 0.05, respectively) became more pronounced in a multivariate analysis, after elimination of the linear effects of body height and energy intake. From the multivariate analysis with combinations of vegetable protein, polysaccharides, and fiber in the equation, fiber appeared to be the most important factor. The gonadotropin and estradiol plasma concentrations were higher in girls who consumed less grain fiber. We conclude that a diet rich in vegetable products, especially fiber, may affect the rate of physical and hormonal sexual maturation, possibly mediated by the hypothalamus-pituitary-gonad system.