This paper presents the development of a tool that allows an organization to assess its level of human factors (HF) and ergonomics integration and maturity within the organization. The Human Factors Integration Toolset (available at: https://www.researchgate.net/project/Human-Factors-Integration-Toolset ) has been developed and validated through a series of workshops with 45 participants from industry and academia and through industry partnered field-testing. HF maturity is assessed across five levels in 16 organizational functions based on any of 31 discrete elements contributing to HF. Summing element scores in a function determines a percent of ideal HF for the function. Industry stakeholders engaged in field-testing found the tool helped to establish the status of HF in the organization, plan projects to further develop HF capabilities, and initiate discussions on HF for performance and well-being. Improvement suggestions included adding an IT function, refining the language for non-HF specialists, including knowledge work, and creating a digital version to improve usability. Practitioner Summary: A tool scoring HF capability in 16 organization functions has been developed collaboratively. Industry stakeholders expressed a need for the tool and provided validation of tool design decisions. Field-testing improved tool usability and showed that, beyond scoring HF capability, the tool created opportunities for discussions of HF-related improvement possibilities.