Understanding how biodiversity persists in the small fragments of forest that remain in many tropical regions is a vital priority. This chapter reviews available studies on liana communities and liana–tree interactions in fragmented tropical forests. Although much remains unknown, it is apparent that lianas often increase dramatically in abundance in fragmented forests. Fragmentation of once-continuous primary forests results in a considerable increase in landscape-wide liana abundance and rates of tree infestation. There are three main reasons for the increase in liana abundance. First, the area of forest edge greatly increases within fragmented forest landscapes and forest edges are preferential liana habitat. Second, elevated rates of large tree mortality, turnover and treefall-gap creation occur in many forest fragments, which again enhance the amount of available disturbed and well-lit habitat preferred by lianas. Finally, initial forest loss and fragmentation may lead to a greater area of forest regeneration (“younger” forest).