OBJECTIVE To examine the association between mother-child communication about sex, sexually transmitted diseases (STDs), and contraception/condoms and HPV vaccine uptake by gender. METHODS Women (n = 1372) with ≥ 1 child aged 9-17 years receiving care in reproductive health clinics in Southeast Texas were asked to complete a self-administered questionnaire between September 2011 and October 2013. RESULTS The majority of mothers with ≥ 1 eligible daughter (n = 886) reported having talked about 'sex' (77.7%), 'STDs' (76.6%) and 'contraception' (73.2%) with their daughters. The respective figures for mothers with ≥ 1 son (n = 836) were 68.8%, 69.0% and 65.3%. Mothers who discussed sex, STDs, or contraception with their daughters compared to those who did not were more likely to report that their daughter initiated (≥ 1 dose) HPV vaccination after adjusting for confounders (all p < .05). Similarly, mother-son discussions about STDs or condoms, but not sex, were associated with HPV vaccine initiation for their sons compared to those who did not discuss these topics. These associations were not significant with regard to HPV vaccine completion (3 doses) for neither daughters nor sons. CONCLUSION Mother-child communication on STDs and contraception/condoms is associated with HPV vaccine initiation, but not completion, among both daughters and sons.