Hepatocellular carcinoma (HCC) continues to be the most prevalent type of liver cancer worldwide. Diethylnitrosamine (DEN)‐induced HCC is an extensively used hepatic cancer model in experimental animals. Acetazolamide (AZA) is a carbonic anhydrase enzyme inhibitor. This study aimed to assess the therapeutic mechanism of AZA against DEN‐induced HCC. Thirty male Wistar albino rats were divided equally into three groups. Group I (C): control group, Group II (HCC): DEN‐induced HCC, and Group III (HCC/AZA): AZA‐treated HCC. Verification of the HCC induced by DEN was confirmed by elevated liver enzymes' activities, and increased α‐fetoprotein (AFP) levels, as well as distinct liver architecture changes. On the other hand, the AZA‐treated HCC group experienced decreases in the activities of serum liver enzymes and AFP levels, as well as, regulated liver architecture. Additionally, it downregulated p‐p38 MAPK/p‐JNK1/JNK2/p‐C‐Jun/p‐NF‐κB p65 protein expressions. Moreover, it ameliorated autophagy by controlling the expression of the p‐AMPK/p‐mTOR1/LC3 I/II proteins. Furthermore, it downregulated the relative gene expressions of carbonic anhydrase‐IX (CAIX) and hexokinase‐II (HKII). Histopathological examination of AZA‐treated HCC liver tissues supported these findings. Conclusion: AZA provides a new dimension in ameliorating experimentally induced HCC through regulation of hepatic biomarkers, antioxidant status, inflammatory markers, and autophagy, mediated by amelioration of CAIX and HKII gene expressions.