Justicia adhatoda linn of family Acanthaceae, with approximately 600 species are found in tropical regions. The plant is well known for its antibacterial, antiulcer, anti-inflammatory, anti- typhoid, anti-gonorrheal, activities. In this study, we investigated the phytochemical constituents of leaves of Justicia adhatoda and performed GC-MS analysis for ethanol extract of the leaves of this plant. Preliminary phytochemical screening of the ethanol extract revealed the presence of alkaloids, flavonoids, tannins, glycosides, phenols, coumarins and xanthoproteins. The GC-MS chromatogram of ethanol extract of Justicia adhatoda showed 15 different peak areas at retention time 4.201 min to 16.372 min. The chromatogram hinted 6-Hydroxy-2-methylcyclohepta(b)pyridin-7-one as a major compound with peak area 28.41% at retention time 9.617 min. followed by 4(hydroxymethyl)cyclopenta-1,3-diene-1-carbaldehyde occupying 15.45% appeared at 4.201 min. Whereas 4 butyl phenol appeared at 6.054 min with peak area 10.81%. Additionally, Antiarol (2.02%), Megastigmatrienone (1.56%), Vasicolin (5.90%) and Carinol (2.78%) were detected at retention time 7.197 min, 7.360 min, 14.142 min and 16.372 min respectively. Furthermore, 9,12,15-Octadecatrien-1-ol 9 (Z,Z,Z), 5-(1-phenylhydrazono) ethyl-Pyrimidine-2,4,6(1H,3H,5H)-trione, 4-Ethyl-2,5-Dimethoxyphenethylamine, 4-hydroxy-3,5,6-trimethyl-4-(3-oxo-1-butenyl)- 2-Cyclohexen-1-one, dimethyl(3-methylbut-2-enyloxy)hexyloxy- silane, [6-Bromo-4-(2-chloro-phenyl)-quinazolin-2-yl]-(4-chloro-phenyl)-amine, Bicyclo[3.2.1]- 2,2,4, 4,8,8-hexachloro-2,4,8-trisila -6-octene, 3-(1-Phenyl-2-pyrazolin-5-yl)indole were also seen in GC-MS Chromatogram.