The objective of this study was to determine the effects of nutritional status on educational performance of the primary school children in the plantation sector in Nuwara Eliya educational zone. A cross-sectional study involving 802 Grade-4 children was conducted on a randomly selected 21 plantation schools in Nuwara Eliya zone. By measuring height and weight using standard methods, indicators such as height-forage , weight-forage and body mass index-forage were computed and used to define stunting, underweight and thinness to indicate nutritional status. The educational performance of children was assessed by using end-term examination marks obtained for Tamil and Mathematics subjects and for the overall subject average. The prevalence of stunting, underweight and thinness in the study group was 32%,50% and 34%, respectively. All indicators were significantly higher (p<0.05) in males than in females. The educational performance of females was higher than males, the differences being statistically significant except in Mathematics (p=0.075). The low level of educational performance (marks<40%) in Tamil, Mathematics and overall subject average was significantly higher (p<0.05) among the underweight and stunted children than that of the normal children. The height-forage and weight-forage Z-scores showed significant positive associations (p<0.05) with Tamil, Mathematics and overall subject average marks while BMI-forage Z-score showed significant positive associations (p<0.05) with only Mathematics and overall subject average. It appears that undernutrition in the primary school children of the plantation sector has led to a low level of educational performance, which could affect their quality of life in the long-term.