Although married women’s safer sex negotiation with their husbands is critical in reducing new HIV infections in Nigeria, its linkage to women’s household decision-making autonomy is less explored in Nigeria. Drawing data from the 2013 Nigeria Demographic and Health Survey and using the logistic regression technique, we examined the associations between women’s household decision-making autonomy and two indicators of the ability to engage in safer sex including whether married women 1) can refuse sex and 2) ask for condom use during sexual intercourse with husbands. Findings indicate that 64% and 41% of married women can refuse sex and ask for condom use, respectively. While the impact of women’s household decision-making autonomy on the ability to refuse sex remained statistically significant after controlling for theoretically relevant variables (OR = 1.15; p < 0.001), its impact on the ability to ask for condom use became weakly significant once socioeconomic variables were controlled (OR = 1.03; p < 0.1). Based on these results, we have two suggestions. First, it may be important that marital-based policies and counselling promote environments in which married women can establish equal power relations with their husbands. Second, it is also important to eliminate structural barriers that hinder married women’s economic opportunities in Nigeria.