<p>Among sub-Saharan African adolescents, delayed HIV and pregnancy disclosure, stigma, and insufficient social support are barriers to engagement in antenatal care and services to prevent mother-to-child transmission of HIV. We developed and evaluated the acceptability and short-term preliminary efficacy of a digitally illustrated, narrative-based intervention designed to address these barriers among Kenyan pregnant adolescents aged 15–19 years living with HIV. We used an iterative, theory-informed, mixed methods human centered design approach. Individual adolescent and dyadic adolescent-caregiver interview data informed the development of an initial prototype (<i>n</i> = 46 adolescents, <i>n</i> = 24 caregivers). We conducted focus groups to assess initial acceptability and obtain feedback on the initial prototype (<i>n</i> = 22 adolescents). Focus group data informed refinement of the prototype, which was then evaluated for acceptability and short-term preliminary efficacy in a single arm pre/post pilot (<i>n</i> = 33 adolescents). The mean age of pregnant adolescents and caregivers was 17.7 years and 47.4 years, respectively. Adolescent interviewees described disclosure as delayed, staged, or indirect rather than immediate and shared accounts of enacted, anticipated, and internalized stigma, coping strategies, family support, and preferences for digital intervention features. Focus group and pilot participants rated key prototype features highly. Over the two-week period from baseline (B) to follow-up (F), pilot analysis showed statistically significant reductions in internalized HIV stigma (B = 1.00, SD = 1.49; F = 0.55, SD = 1.12; <i>p</i>=.03; d = 0.43) and anxiety symptoms (B = 5.03, SD = 4.83; F = 3.45, SD = 3.80; <i>p</i>=.02; d = 0.46). Findings also suggested improvements in self-efficacy for knowing when it is safe to disclose HIV status (B = 6.24, SD = 3.75; F = 7.59, SD = 3.79; <i>p</i>=.05; d = 0.38) and pregnancy status (B = 5.52, SD = 4.76; F = 8.21, SD = 3.59; <i>p</i>=.002; d = 0.63), fewer reports of difficulty with HIV and pregnancy disclosure, increased perceived social support (B = 54.41, SD = 16.12; F = 60.28, SD = 17.53; <i>p</i>=.02; d = 0.48), and overall improvements across other targeted psychosocial outcomes. This digitally illustrated, narrative-based intervention shows promise for strengthening disclosure and stigma-coping skills among pregnant adolescents in low resource settings, thereby empowering them to seek needed support from caregivers and improving their overall health and wellbeing.</p><p><i>Clinical Trials Registration</i>: The study is registered at clinicaltrials.gov under ID Number NCT05383755.</p>