The study focused on the determinants of commercial bank deposits in Zimbabwe's banking sector during the multiple currency period (2009 to 2017). A total of 13 registered banks were used in this study. Results from the random effects model exhibited that number of branches, deposit interest rate, liquidity and economic growth were positively significant in influencing the commercial banks' deposits. The results infer that both bank-specific (internal) factors and macroeconomic (external) factors affect the deposit mobilisation ability of commercial banks in Zimbabwe under a multi-currency system. The study recommended that commercial banks open more branches to be more accessible to society. The Reserve Bank of Zimbabwe (RBZ) is encouraged to prudently supervise and regulate commercial banks so that liquidity crunch and related risks can effectively be managed. Commercial banks are recommended to increase the deposit interest rates to attract more deposits, thereby increasing their capacity to finance capital projects. Keywords: Bank-specific factors, Commercial bank deposits, Deposit mobilisation, Macroeconomic factors, Multiple currency system, Panel data approach, Zimbabwe.