Background: Ficus deltoidea Jack or locally known as Mas Cotek belongs to the family Moraceae is a conventionally used Malaysian native medicinal plant. Objectives: The aim is to determine the anti-inflammatory mechanism of various solvent fractions of F. deltoidea methanol extract against Lipopolysaccharide (LPS)-induced nuclear factor-kappa B (NF-κB) inflammatory pathway in murine macrophage 264.7 cells and to identify the chemical constituents present in the active fraction. Materials and Methods: The effect of crude methanolic extract and its fractions (hexane, chloroform, ethyl acetate, and butanol) on murine macrophages against LPS-induced pro-inflammatory cytokines (interleukin [IL]-Iβ, tumor necrosis factor alpha [TNF-α], and IL-6) and biomarkers were tested using enzyme-linked immunosorbent assay and immunoblot analysis. The chemical constituents present in the active fraction were identified using liquid chromatography mass spectrometry and liquid chromatography tandem mass spectrometry analysis. Results: The findings indicated that among all the fractions, the ethyl acetate fraction of F. deltoidea substantially inhibits the LPS-induced inflammatory mediators such as nitric oxide (NO) and pro-inflammatory cytokine production including TNF-α, IL-6, and IL-1 β in a dose-dependent manner. The expression of inducible NO synthase, NO synthase, and cyclooxygenase-2 were also effectively downregulated by the treatment of ethyl acetate fraction. Moreover, it also suppressed the expression of LPS-induced NF-κB translocation correlated with the inhibition of NF-κB (inhibitor of kappa B alpha) degradation. The presence of bioactive phenolics, especially flavonoids such as catechin, vitexin, dodecadienyl coumaric acid, (epi)-afzelechin-(epi)-catechin, genistein, and apigenin derivatives were identified in the ethyl acetate fraction of F. deltoidea. Conclusion: Overall, it has been recommended that the ethyl acetate fraction of F. deltoidea could be utilized as a potential natural anti-inflammatory agent.