Abstract Background Self-injection (SI) of subcutaneous depot medroxyprogesterone acetate (DMPA-SC) is a self-care intervention (drugs, diagnostics, or devices that can be provided mostly outside the health system) implemented across Nigeria. Per national guidelines, first-time DMPA-SC users can obtain units for SI after two in-person training visits. Success of self-care interventions, the option for SI included, depends on local policies and individual providers to create an enabling environment. Thus, we aimed to 1) assess providers’ fidelity to Ministry of Health protocols; 2) assess the extent of bias in fidelity; and 3) to asses client-centeredness. Methods Eight mystery client actors portrayed an older, married woman or a younger, unmarried woman without DMPA-SC experience. They sought contraception, including DMPA-SC for SI, at 30 public and 30 private facilities. A total of 120 interactions were planned (two per facility—one by each profile). Immediately following their interactions, actors completed a debrief survey about their experiences. Using responses from these debrief surveys, we described key actor-reported outcomes (providers’ fidelity to Ministry of Health protocols for SI dispensing, SI training, and supporting contraceptive decision-making). We also examined objective and subjective client-centeredness outcomes. We assessed bias in fidelity and client-centeredness through bivariate tests for differences by actor profile (younger/unmarried vs older/married) and facility type (health facility vs pharmacy/PPMV). Results Fidelity to dispensing guidelines (i.e., refusing DMPA-SC units for SI) differed by facility type (χ2 = 12.4, p-value < 0.001). Descriptively, pharmacists/PPMVs more often broke with protocol and were willing to dispense DMPA-SC units. Similarly, fidelity to Ministry of Health training guidelines on DMPA-SC for SI differed by facility type (χ2 = 9.9, p-value = 0.007). Client-centeredness outcomes (e.g., being asked about and feeling treated differently based on age and marital status) were found to differ by actor profile. Descriptively, more of the younger, unmarried profile actors reported these outcomes compared to older, married profile actors. Conclusions Willingness to dispense DMPA-SC for SI differed by facility type but not by client profile. However, younger, unmarried profile actors experienced more scrutiny from providers. These findings indicate a need for clarifying service provision protocols to ensure an enabling environment for women’s access to and use of self-injectable contraception.