Background: Establishment of sister chromatid cohesion N-Acetyltransferase 2 (ESCO2) is a gene implicated in the establishment of sister chromatid cohesion (SCC) and cell proliferation. We aimed to explore how ESCO2 affects the proliferation of hepatocellular carcinoma (HCC). Methods: We analyzed ESCO2 expression levels and their association with clinical prognosis using the TCGA, HCCDB, and ICGC databases. Bioinformatics methods were employed to investigate potential regulatory pathways involving ESCO2. CCK-8 assays, colony formation assays, and flow cytometry were used to examine the impact of ESCO2 knockdown on the malignant biological behavior of HCC cells. Western blotting was utilized to identify the specific regulatory mechanism of ESCO2. Results: ESCO2 was significantly upregulated in HCC tissues and correlated with a worse prognosis. Bioinformatics analysis revealed that ESCO2 regulated pathways related to the cell cycle and cell proliferation. Furthermore, knockdown of ESCO2 significantly inhibited HCC cell proliferation both in vivo and in vitro. Most importantly, ESCO2 stimulated the PI3K/AKT/mTOR pathway, which ultimately accelerated the cell cycle and inhibited apoptosis, promoting HCC progression. Conclusion: The present study elucidated the mechanism by which ESCO2 regulates HCC proliferation: ESCO2 promotes HCC proliferation by accelerating the cell cycle and inhibiting apoptosis via the PI3K/AKT/mTOR signaling pathway.