Improvements spearheaded by the World Health Organization in antenatal HIV counseling in sub-Saharan Africa from 2004 to 2011 have seen a parallel increase in HIV testing. We sought to determine the extent to which the use of choice architecture principles (one that introduces an opt-out option as the default) affect uptake of HIV testing, above and beyond individual-level attitudes and cognitions. Demographic and Health Survey data collected between 2004 and 2011 from Zimbabwe (N = 1,330) and Malawi (N = 4,043)—countries where over 10% of adults have HIV—were analyzed. We explored the influence of demographic variables, modes of knowledge about HIV, stigma against people living with HIV, attitudes about spousal abuse, and whether or not HIV testing had been offered during antenatal visits. Results demonstrated that, taking into account secular trends in higher testing rates, structural-level support was the strongest predictor of HIV testing above and beyond individual-level attitudes and cognitions.