Anopheles sundaicus (s.l) is a widely distributed species complex ranging across many South-East Asian countries. Members of the complex are distributed throughout India, Myanmar, Cambodia, Malaysia, Vietnam and surrounding islands including Java, Sumatra and Borneo (

Recent research has found the species complex to include five genetic forms named A, B, C, D and E, all species are similar in their association with brackish, coastal waters. However, variance exists between species with some inland populations recorded in India, Malaysia, Borneo, Sumatra, Java and Indonesia. Inland species were associated with fresh water; these ecological and behavioural differences led to the species being divided into a complex ( ).

This convoluted species still needs more work as recent research has now found up to eight genetically distinct groupings within the complex ( Ecological and behavioural plasticity between species within the group is important in the transmission and control of malaria. Some species in the group are major or secondary vectors of malaria along coastal regions of India, Vietnam and Indonesia. However, in coastal areas of Thailand, Cambodia and Malaysia the role of An. sundaicus (s.l) in malaria transmission is uncertain (

Anopheles sundaicus is generally considered endophilic and anthropophilic, however populations have also been found to exhibit exophily and zoophily, which has implications for vector control ( .