Objectives Andrographis paniculata leaves have been widely used in traditional medicine due to their rich content of phenolic compounds. We sought to figure out the skin beneficial effects of Andrographis paniculata leaves extract. Methods In this study, we evaluated the total phenolic and flavonoid content of Andrographis paniculata leaf extracts (ALE), as well as its antioxidant activities against diphenyl-2-picrylhydrazyl, ABTS, and hydrogen peroxide radicals. Additionally, we conducted cell viability assays, reverse transcriptase polymerase chain reaction , and western blot analysis to investigate the biochemical effects of ALE on UVB-induced HaCaT cells. Results Our results revealed that ALE exhibited a high concentration of polyphenols and flavonoids, which were associated with potent abiotic antioxidant properties. Furthermore, ALE treatment effectively abrogated the damage caused by UVB radiation on key molecules such as hyaluronan synthase 1, aquaporin 3, and loricrin in HaCaT cells. ALE also demonstrated the ability to reduce the overactivation of mitogen-activated protein kinases and the expression of pro-inflammatory cytokines, including interleukin-6 (IL-6) and IL-1β in UVB-induced HaCaT cells. Additionally, ALE positively influenced the peroxisome proliferator-activated receptor alpha in these cells. Conclusion Overall, our findings highlight the antioxidant and anti-inflammatory effects of ALE, as well as its significant role in modulating skin barrier functions. These results contribute to the growing body of evidence supporting the therapeutic potential of ALE in skincare and dermatological applications.