This study was conducted to assess the genetic variability and correlation of phenotypic characteristics in 12 tomato (Solanum lycopersicum L.) genotypes including 11 WorldVeg and one commercial variety (Pusa Ruby) in Terai (plain) region of Nepal in 2021–2022. This experiment was laid out in a randomized complete block design with three replications. The phenotypic traits, including days to 50% flowering, plant vigor and height, fruit number/plant, fruit yield, fruit weight and diameter, fruit firmness and fruit pericarp thickness, and total soluble solids (TSS) content of the fruits, were studied. Analysis of variance revealed significant differences among the genotypes for all the traits except for plant vigor. The genotype of AVTO1705 resulted the highest fruit yield (2.9 kg/plant) than Pusa Ruby, a commercial check (0.5 kg/plant). The phenotypic coefficient of variation (PCV) was higher than the genotypic coefficient of variation (GCV) for all the traits and PCV values were maximum for the number of fruits, fruit yield, and fruit weight. High PCV, GCV, and genetic advance (GA) were observed for yield, fruit weight, and plant height, respectively, indicating the additive gene effect. High heritability for fruit yield/plant and plant height inferred the phenotypic selection for their genetic improvement. Fruit yield was significantly (P<0.05) positively correlated with the fruit number and fruit weight, and direct selection of these traits are reliable for yield improvement in tomato.