Metabolic associated steatotic liver disease (MASLD) is a condition of poor liver health induced by excess accumulation of lipid in the liver. MASLD currently affects >5.5 million Australians and is strongly associated with obesity, diabetes and cardiovascular disease. MASLD can also progress to metabolic associated steatohepatitis (MASH), a mostly irreversible condition characterized by hepatic fibrosis and inflammation, in addition to steatosis. MASH is a major risk factor for cirrhosis and liver cancer, explaining its prediction of becoming the leading cause of liver transplantation within the next two decades. Despite this worrying disease burden, there are currently few effective treatments for MASLD and MASH, due in part to existing knowledge gaps in our understanding of the cellular and molecular mediators of disease development. To address this gap, we undertook a study to characterise the liver cellular landscapes of mice exposed to a MASH initiating diet (Amylin NASH diet; AMLN) using single-cell transcriptomics. This was performed across 3 time points (2, 8 & 24 weeks) in both male and female C57BL/6J mice. We dissociated livers from n=4 animals of each group together with their control diet counterparts and analysed single cell data from all 48 mice. Our analysis yielded a dataset comprising ~88,000 hepatic cells. Cellular composition and gene expression differences between cells of different time points reflected different phases of AMLN diet-induced liver remodelling. Specifically, we demonstrated a surprisingly acute remodelling of the liver cellulome within just 2 weeks of AMLN diet, characterised by a 3-4 fold increase in immune cells in male mice, and female specific expansion of cholangiocyte populations. After 24 weeks of AMLN diet, where MASH was readily apparent, we identified a clear fibrotic signature, with altered stellate cell abundance and gene expression, and metabolic rewiring of hepatocyte metabolism. Of particular note, was the identification of an intriguing “bipotent” progenitor cell-type that was apparent only in livers from mice with significant MASH, providing evidence for the existence of a novel, potentially targetable, disease repair mechanism. Thus, this dataset provides an unprecedented insight into the sex specific mechanisms that drive and potentially protect from MASH, providing new knowledge towards the discovery of novel diagnostics and therapeutics.