The proliferation of fintech applications in emerging markets necessitates a robust understanding of mobile usability factors driving consumer retention. This study quantitatively examines the relationship between user experience (UX)/user interface (UI) attributes and retention intentions within Nigeria's fintech sector. Employing a cross-sectional design, structured online survey data were collected from N = 248 active users of prominent fintech applications (e.g., Opay, PalmPay). Multiple linear regression analysis was conducted to assess the predictive power of key usability constructs—Navigation Ease, Visual Appeal, Performance Speed, and Functionality—on consumer retention. Results revealed that Navigation Ease (β = 0.34, p < .001) and Performance Speed (β = 0.29, p = .002) were significant positive predictors of retention, explaining a substantial proportion of variance (R² = 0.63). Visual Appeal exhibited a modest yet significant influence (β = 0.18, p = .041), while Functionality did not reach statistical significance (β = 0.07, p = .110). The study concludes that in emerging markets like Nigeria, intuitive navigation and high performance speed are paramount usability factors for fostering fintech consumer retention. Fintech providers should prioritise these elements in UX/UI development over comprehensive functionality, particularly where infrastructural constraints exist. Strategic investment in locally relevant, highperformance design is therefore essential for sustainable growth in competitive fintech ecosystems.