The present invention relates to a stable oral liquid pharmaceutical composition of celecoxib or pharmaceutically acceptable salts thereof. The celecoxib present in the compositions as described herein do not show any precipitation when subjected in Fasted- State Simulated Gastric Fluid (FaSSGF) at pH 2.0, temperature of 37°C ± 0.5°C and under stirring at a speed of 50 rpm at least for 60 minutes. It also relates to the process of preparing and method of using said composition of celecoxib.