The study examined the relationship between parental socio-economic status and pupils' performance in Primary Leaving Examinations (PLE) in government primary schools in Buyinja Sub-county. Socio-economic status was measured through parental income, educational attainment, and occupational status. A cross-sectional survey design was adopted, and data were collected from 473 respondents comprising pupils, parents, and teachers. Structured questionnaires and interview guides were used as instruments. Results revealed a statistically significant positive relationship between all three SES indicators and PLE performance. Pupils from higher-income households, with better-educated parents, and parents in professional occupations consistently attained higher PLE grades. The study concluded that parental socio-economic status was a strong predictor of academic achievement at the primary level in Buyinja Sub-county. It was recommended that government and education stakeholders design targeted support interventions for pupils from economically disadvantaged households to bridge persistent performance gaps.