Additive manufacturing has gained worldwide popularity in the last 20 years as many different methods and technologies for adding materials have been developed. Among them, wire and arc additive manufacturing (WAAM) is a promising alternative for fabricating high quality aerospace metal components economically. This study introduces a process planning strategy for WAAM that produces the path and parameters for the deposition process from CAD and process models. After introducing the framework for process planning, two important steps, tool-path generation and optimization of welding parameters, will be presented in detail. Based on the general requirements for a good quality AM tool-path, including high geometrical accuracy and a minimal number of tool-path passes and elements, two novel tool-path patterns suitable for various geometries are introduced. Using the proposed weld bead model and the overlapping model, appropriate welding parameters, such as the travel speed, wire-feed rate, and layer thickness, can be determined. The performance of the proposed process planning strategy is verified through building a sample impeller.