The anti-inflammatory activities of Sida cordifolia leave extract were scientifically stated. However, no report has yet been published about the active component responsible for anti-inflammatory activity of Sida cordifolia leaves extract. It was intended to isolate the flavonoids from the Sida cordifolia leaves extract and investigated its anti-inflammatory efficacy. Petroleum ether and ethanol extract were extracted out from the powdered of leaves. The phytochemical study was done for both extracts. The in vitro antioxidant activity was performed on ethanol extract on different models. The column chromatography was used for the isolation of flavonoid from ethanol extract, and further anti-inflammatory potency of the isolated compound was investigated. The phytochemical study indicates flavonoids and polyphenol were present in ethanol extract. The higher antioxidant activity was observed in ethanol extract from findings of antioxidant study. The isolated flavonoids exhibited Rf value of 0.46 on solvent ratio of chloroform: methanol (1:1), which was similar to standard quercetin. The significant anti-inflammatory activity was found for isolated flavonoid against carrageenan-induced edema and cotton pellet-induced granuloma in experimental animals. The findings confirmed that the flavonoid present in the Sida cordifolia demonstrated anti-inflammatory activity.