The present study describes the comparative evaluation of phytoconstituents and in vitro antioxidant activity of ethanolic crude extracts of selected plant parts (stem) of Andrographis lineata (AL) and Andrographis serpyllifolia (AS). The ethanolic crude extracts of Andrographis lineata stem (ALS) and Andrographis serpyllifolia stem (ASS) were analyzed for the presence of phytoconstituents (qualitative and quantitative) and further assayed for in vitro free radical scavenging assays namely-DPPH (1,1-diphenyl-2-picrylhydrazil), nitric oxide, total reducing power, lipid peroxidation and superoxide radical scavenging assays. In all the in vitro assays ASS showed its ability to scavenge free radicals in dose dependent manner than ALS which was comparable to the standards. Further the extracts (ALS and ASS) were analyzed in GC-MS for its chemical composition which revealed the presence of high content of flavones, glycosides unsaturated fatty acids and phenolic compounds in ASS which may be responsible for higher antioxidant capacity than the ALS extracts.