Abstract Background Despite significant interest in integrating sexual and reproductive health (SRH) services into HIV services, less attention has been paid to linkages in the other direction. Where women and girls are at risk of HIV, offering HIV testing services (HTS) during their visits to family planning (FP) services offers important opportunities to address both HIV and unwanted pregnancy needs simultaneously. Methods We conducted a systematic review of studies comparing FP services with integrated HTS to those without integrated HTS or with a lower level of integration (e.g., referral versus on-site services), on the following outcomes: uptake/counseling/offer of HTS, new cases of HIV identified, linkage to HIV care and treatment, dual method use, client satisfaction and service quality, and provider knowledge and attitudes about integrating HTS. We searched three online databases and included studies published in a peer-reviewed journal prior to the search date of June 20, 2017. Results Of 530 citations identified, six studies ultimately met the inclusion criteria. Three studies were conducted in Kenya, and one each in Uganda, Swaziland, and the USA. Most were in FP clinics. Three were from the Integra Initiative. Overall rigor was moderate, with one cluster-randomized trial. HTS uptake was generally higher with integrated sites versus comparison or pre-integration sites, including in adjusted analyses, though outcomes varied slightly across studies. One study found that women at integrated sites were more likely to have high satisfaction with services, but experienced longer waiting times. One study found a small increase in HIV seropositivity among female patients testing after full integration, compared to a dedicated HIV tester. No studies comparatively measured linkage to HIV care and treatment, dual method use, or provider knowledge/attitudes. Conclusions Global progress and success for reaching SRH and HIV targets depends on progress in sub-Saharan Africa, where women bear a high burden of both unintended pregnancy and sexually transmitted infections, including HIV. While the evidence base is limited, it suggests that integration of HTS into FP services is feasible and has potential for positive joint outcomes. The success and scale-up of this approach will depend on population needs and health system factors.