Objectives : We tried to uncover the anti-lipogenic effect and underlying mechanism of Laminaria japonica on an experimental cellular model of non-alcoholic fatty liver disease. Methods : Ethanol extract of Laminaria japonica (LJ) was prepared. Intracellular lipid content of palmitate-treated HepG2 cells was evaluated with or without LJ treatment. We measured the effects of LJ on liver X receptor ${alpha}$ ($LXR{alpha}$) and sterol regulatory element-binding transcription factor-1c (SREBP-1c) expression, transcription level of lipogenic genes, including acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), stearoyl-CoA desaturase-1 (SCD-1), and nuclear factor erythroid 2-related factor 2 (Nrf2) activation in HepG2 cells. Results : LJ markedly attenuated palmitate-induced intracellular lipid accumulation in HepG2 cells. LJ suppressed $LXR{alpha}$-dependent SREBP-1c activation, and SREBP-1c mediated induction of ACC, FAS, and SCD-1. Furthermore, LJ activated Nrf2, which plays an important cytoprotective role in non-alcoholic fatty liver disease. Conclusions : Our study suggests that LJ has the potential to alleviate hepatic lipid accumulation, and this effect was mediated by inhibiting the $LXR{alpha}$-SREBP-1c pathway that leads to hepatic steatosis. In addition, the anti-lipogenic potential may, at least in part, be associated with activation of Nrf2.