Tomato grown during late winter in plains of Nepal suffers from high temperature stress which causes severe reduction in fruit yield. Thus, this study was conducted to evaluate yield potential of nine tomato genotypes under seasonal heat stress. Analysis of variance showed significant differences (p ≤ 0.05) among all genotypes for all measured traits. The highest mean marketable fruit yield of 101.6 t ha^-1 was recorded from genotype TO-1057 whereas AVTO-9802 produced the lowest mean fruit yield of 32.9 t ha^-1. Path coefficient analysis revealed that the high positive direct effect was noted for marketable fruit per plant (0.99), followed by average fruit weight (0.795). Correlation analysis revealed that plant height, fruit weight and diameter were positively associated with fruit yield. Fruit diameter showed positive and significant correlation with average fruit weight (0.983***). In GGE Biplot, 80.74% of variation explained by PC1 and PC2. Srijana was at the vertex of the polygon and governed by the major traits. Likewise, genotypes TO-1057, Pariposa-4102 and Srijana were grouped in one cluster. Tomato genotypes with semi-determinate to indeterminate growth habit with medium sized fruits performed better in the experiment. This study suggests that the genotype TO-1057 and Srijana could be recommended for summer season cultivation in the plains of Chitwan.