The rapid proliferation of smartphones among secondary school students has transformed the contemporary learning environment, creating opportunities for digital learning while simultaneously raising concerns about digital distraction and its implications for students' academic performance. This study investigated smartphone use patterns and academic outcomes among students in Nigerian public secondary schools, focusing specifically on educational smartphone use, recreational use, screen time, classroom phone use, attention, self-regulated learning, and differences associated with school location. A quantitative cross-sectional research design was adopted. The study comprised 900 senior secondary school students drawn from nine Nigerian public secondary schools, including four urban and five rural schools. The sample consisted of 450 students from urban schools and 450 from rural schools, with equal representation of 300 students each from SS1, SS2, and SS3. Validated measures of educational smartphone use, recreational smartphone use, classroom phone use, attention, and self-regulated learning demonstrated satisfactory reliability, with Cronbach's alpha coefficients ranging from .84 to .91. Findings revealed a significant positive relationship between educational smartphone use and academic outcomes (r = .41, p < .001), suggesting that purposeful academic engagement with smartphones was associated with improved achievement. In contrast, recreational smartphone use showed a significant negative relationship with academic outcomes (r = -.38, p < .001). Phone use during classroom instruction was also negatively associated with students' attention levels (r = -.29). Furthermore, moderation analysis indicated that the negative effect of recreational smartphone use was approximately 1.7 times stronger among students in rural schools, with a significant interaction effect (beta = -.22, p < .001). The regression model incorporating prior academic performance, educational smartphone use, and recreational smartphone use explained 52% of the variance in academic outcomes (R² = .52). The study concludes that the educational consequences of smartphone use depend substantially on the purpose, intensity, context, and regulation of use rather than smartphone access alone. Nigerian public secondary schools should therefore promote purposeful digital learning, strengthen students' digital self-regulation, regulate distracting smartphone use during instruction, and improve digital learning resources, particularly in rural schools.