The high rate of deforestation and fragmentation of elephant habitat on Sumatra Island has triggered human-elephant conflict (HEC) in Sumatra Island, Indonesia. This conflict brings negative impacts on humans and elephants. Despite numerous efforts having been made to solve this problem, the HEC continues to occur in the remaining elephant enclave every year. The harmonious coexistence between humans and elephants could be improved through HEC mitigation programs. The aim of this paper was to review information on HEC in Sumatra Island, investigate the causes and implications of HEC, review existing HEC mitigation methods, and formulate strategies to improve the harmonious coexistence between humans and elephants. The best strategies to create successful human and elephant coexistence are strengthening the institutions and policies, restoring the habitat, developing wildlife corridors, establishing Essential Ecosystem Areas (EEA), community empowerment through ecotourism, providing legal access to forests through Social Forestry (SF), and providing compensation schemes for conflict victims.