<p>Sucking pests, including thrips (<i>Thrips tabaci</i>), aphids (<i>Aphis gossypii</i>), jassids (<i>Amrasca biguttula biguttula</i>) and whiteflies (<i>Bemisia tabaci</i>), are among the most destructive insect pests limiting cotton (<i>Gossypium spp</i>.) productivity. Understanding their population dynamics in relation to plant morphological traits is essential for developing pest-tolerant genotypes. An experiment was conducted during <i>Kharif</i> 2023–24 using five lines, four testers, their twenty F₁ hybrids, and two checks in a randomized block design at the Cotton Research Station, Nanded, Maharashtra, India. The study examined pest dynamics (30–90 DAS) and their association with trichome density and leaf thickness. Among hybrids, the lowest mean aphid population (2.73 aphids per 3 leaves) was observed at 90 DAS. Similarly, the lowest mean populations of jassids, thrips and whiteflies were recorded at 2.87, 2.72 and 2.56 per 3 leaves, respectively, at all 30 DAS. Significant genotypic variation was also observed for trichome density and leaf thickness. Leaf pubescence pattern showed light hairy on the adaxial surface and both light hairy and hairy on the abaxial surface. Trichome density showed a significant negative correlation with jassids, thrips, and aphids, but a significant positive correlation with whiteflies, whereas leaf thickness exhibited the opposite trend, with significant positive correlations with jassids, thrips, and aphids and a significant negative correlation with whiteflies. The findings highlight the role of leaf morphological traits in conferring resistance to sucking pests and provide useful insights for breeding cotton cultivars with improved pest tolerance.</p>