HIV testing remains an important part of HIV prevention and treatment programs. Interventions to encourage testing may be more effective if they can be tailored to audiences with different readiness for testing. We sought to determine characteristics differentiating people who had tested from those who had not but were interested, and people who were interested from people who had not tested and were not interested in testing. We analyzed survey data from 2671 adults in Namibia, investigating demographic, psychosocial, interpersonal, behavioral, and access to care-related factors that might differentiate the groups. Findings indicated that the interested group differed from the not interested group on factors such as knowledge of testing locations and about HIV medications, higher perceived susceptibility for getting HIV, lower stigma toward people with HIV, and more positive interpersonal factors like more social support and discussion about HIV. The tested group differed from the interested group on factors relating to life stage and socioeconomic status, such as being older, more educated, having more access to amenities, being less likely to be a student, and more likely to be living with a sexual partner, along with access-related factors such as access to counseling resources and testing clinics. Consistent with results from stage-based behavior change studies, interest in HIV testing among the untested may be related more to knowledge, attitudes, and social openness about HIV, while testing behavior among the interested may be related more to socioeconomic and access-related barriers. As such, interventions tailored for these different audiences may be more effective than a single intervention to promote testing.