The aim of our study was to determine the effects of social dominance in dairy heifers during the prepuberal period on body growth, follicle development and age of onset of cyclic activity. Sixteen Holstein dairy heifers (8.2 ± 0.3 mo-old, 208.5 ± 13.9 kg BW) were homogeneously allocated according to age and BW to 8 dyads. Each dyad was housed in a different pen separated by electrical fences, had access to only one feeder and received a total mixed ration on a 5% restriction of their potential total dry matter intake to promote competition between heifers. Social dominance (dominant-DH, subordinate-SH) was determined every 30 d in each dyad during the 120 d of the experiment. Heifers were weighed every 20 d, and the number of follicles, the maximum follicle diameter (MFD) and presence of corpus luteum (CL) were determined every 7 d by transrectal ultrasound. Puberty onset was defined as the first day in which a CL—confirmed in the following observation—was recorded. Body weight and follicular parameters were analyzed with an ANOVA for repeated measures, while age at puberty was compared with a paired t-test. At the end of the experiment, DH were heavier than SH heifers (312.4 ± 2.5 vs. 304.0 ± 2.5 kg for DH and SH respectively, P = 0.006). In addition, DH reached puberty earlier than SH (318.0 ± 17.5 vs. 330.0 ± 23.3 d, for DH and SH, respectively; P < 0.05), and presented greater MFD from d 53 until the end of the experiment (10.0 ± 0.5 vs. 8.3 ± 0.5 mm, DH and SH heifers; P = 0.04). There was an interaction between social dominance and day of the study for total number of follicles: SH had more follicles than DH heifers on d 70 (4.8 ± 1.1 vs. 8.6 ± 1.1, DH and SH, P < 0.01), 79 (4.3 ± 1.1 vs. 7.7 ± 1.1, DH and SH, P < 0.01) and 86 (4.2 ± 1.1 vs. 6.8 ± 1.1, DH and SH, P = 0.04). No differences were found on the number of follicles >6 mm between groups (1.7 ± 0.3 vs. 2.0 ± 0.3, DH and SH, respectively; P > 0.05). In conclusion, with a slight restriction of food availability, dominant heifers presented greater body growth and reproductive development than subordinate ones. Financial support: CSIC, Uruguay.