Line x Tester analysis was performed by employing fourteen tomato genotypes (10 lines and 4 testers) to develop 40 hybrids. These hybrids along with parental lines and commercial check Naveen 2000+ were evaluated to know the extent of heterosis exhibited to different yield and yield attributing traits. Results revealed that nine hybrid combinations produced significantly increased heterotic effect over the better parent. The top best 5 such combinations were; EC-5863 x Solan Lalima, EC-5863 x Solan Vajr, CLN 2123 A-1 x Solan Lalima, EC-526146 x Solan Lalima and CLN 2123 A-1 x Solan Vajr which registered superiority in term of yield/plant and yield/hectare to the tune of , , , and per cent, respectively over the better parent. Whereas, 6 cross combinations, reported significant positive heterosis over the standard check viz. EC5863 x Solan Lalima ( %) followed by EC-5863 x Solan Vajr ( %), CLN 2123 A-1 x Solan Lalima ( %), EC-526146 x Solan Lalima ( %), CLN 2123 A-1 x Solan Vajr ( %) and EC-521041 x Solan Lalima ( %) these hybrids also reported heterosis for yield attributing traits. | Heterosis studies for yield and yield attributing traits in tomato (Solanum Lycopersicum L.) under north western Himalayan region, India