Aim Due to the important role of lianas in the functioning of forest ecosystem knowledge of the factors that affect them are important in the management of forests. Currently there are conflicting reports on the response of liana communities to disturbance calling for more research in the area. The present study was carried out to investigate the response of liana diversity and structure to human disturbance within two major forests in the Penang National Park Malaysia. The study also looked at the implication of the findings for conservation.\n\nMethods A total of 15 40 × 40-m2 (or 40-m × 40-m) plots each were randomly located across a range of habitats in a primary forest and disturbed secondary forest. Trees with diameter at breast height =10 cm were examined for lianas with diameter =2 cm. Both lianas and trees were enumerated and compared between the two forests. Diversity and structural variables of lianas were compared between the two forests using the t-test analysis. Tree abundance was also compared between the two forests with t-test while linear regression analysis was run to determine the effects of tree abundance on liana abundance.\n\nImportant Findings A total of 46 liana species belonging to 27 genera and 15 families were identified in the study. Human disturbance significantly reduced liana species richness and species diversity in the secondary forest. Liana abundance remained the same in both forests whereas liana basal area was