Background: Numerous degenerative diseases are brought on by inflammation and oxidative stress. Metabolites from plants contain anti-inflammatory and antioxidant properties. Indigenous and understudied, Thottea sivarajanii is a significant ethnobotanical herb. It is native to the Western Ghats and belongs to the Aristolochiaceae family. Objectives: The current study investigated the antioxidant and anti-inflammatory properties of T. sivarajanii leaf methanol extract (TSL) and the insights provided by phytochemical analysis. Methods: The HRLC–MS/MS (Q-TOF) study is used for the phytochemical analysis. The antioxidant efficacy is evaluated in terms of DPPH and ABTS radical scavenging, and reducing power (FRAP assay). In vitro anti-inflammatory efficacy was evaluated on RAW 264.7 cells challenged with lipopolysaccharide (LPS). Result: The HRLC–MS/MS (Q-TOF) study indicated the presence of bioactive molecules such as ursolic acid, Daidzein 4’,7-diglucoside, Calophyllin B, and Berbamine, etc. The results showed in vitro antioxidant capacity in DPPH, and ABTS, radical scavenging, and ferric-reducing activities with respective IC₅₀ and EC₅₀ values of 184.5 ± 2.4, 24.15 ± 0.13, and 4.94 ± 0.32 µg/mL, respectively. LPS significantly stimulated the production of IL-1β, IL-6, and TNF-α in RAW 264.7 cells (p < 0.001). Treatment with TSL reduced levels of IL-1β and IL-6 from 776.1 ± 11.4 and 1678.1 ± 12.4 to 195.4 ± 9.2 and 465.4 ± 11.8 pg/mg protein. It also reduced NO levels from 91.4 ± 1.3 to 30.8 ± 1.7 µM/mg protein while reducing TNF-α levels from 2041.2 ± 15.1 to 1037.5 ± 15.4 pg/mg protein. Conclusions: This work contributes to the growing evidence supporting the pharmacological importance of the underexplored Thottea sivarajanii, highlighting this species as a promising candidate for natural antioxidant and anti-inflammatory agents.