An alien plant also referred to as exotic, introduced, foreign, non-indigenous or non-native, is one that has been introduced by humans intentionally or otherwise through human agency or accidentally from one region to another. Those naturalized aliens that become so successful as to spread in the flora and displace native biota or threatens valued environmental, agricultural, or personal resources by the damage it causes are considered invasive. Devarayanadurga Reserve Forest (DRF) in Tumakuru District is a tropical dry deciduous type, comparatively dense forest with predominant tree species. It is known for harboring varieties of medicinal plants. During the present study a total of 144 Invasive Alien Species (IAS) belonging to 130 genera of 51 families were recorded. Fabaceae is the dominating invasive family with 27 species followed by Asteraceae and Malvaceae with 11 and 8 species respectively. 105 IAS were reported to be affecting ecosystem functions and services, 56 IAS to be causing biodiversity loss and 81 IAS to be causing economic loss and health hazards of either human or wildlife or both. 111 IAS shows continuous spread in DRF with range extension. IAS affects the ecosystem of the region, the economy of the surroundings, habitat destruction, biodiversity loss, human health, and livelihood. Hence timely monitoring of the phenology and distribution pattern studies of IAS should be undertaken to successfully eradicate them and re-establish native species.