A method, system, and apparatus are provided for exposing and calling workbook models via remote function calls. According to the system, a client computer executes a spreadsheet program for creating a workbook model. The workbook model may be published to a server computer along with data defining a function name and the cells that should be used as inputs and outputs to the model. The system also includes a server computer that receives and responds to remote function calls directed toward workbook functions. When a function call is received at the server computer for a workbook function, the server computer populates the cells in the workbook identified as inputs with input parameters received with the function call and recalculates the workbook. The data contained in the output cells is then returned as a reply to the remote function call.