Organizational information system users (OISU) that are victimized by cyber threats are contributing to major financial and information losses for individuals, businesses, and governments. Moreover, it has been argued that cybersecurity competency is critical for advancing economic prosperity and maintaining national security. The fact remains that technical cybersecurity controls may be rendered useless due to a lack of cybersecurity competency of OISUs. All OISUs, from accountants to cybersecurity forensics experts, can place organizational assets at risk. However, that risk is increased when OISUs do not have the cybersecurity competency necessary for operating an information system (IS). The main goal of this research study was to propose and validate, using subject matter experts (SME), a reliable hands-on prototype assessment tool for measuring the cybersecurity competency of an OISU. To perform this assessment, SMEs validated the critical knowledge, skills, and abilities (KSA) that comprise the cybersecurity competency of OISUs. Primarily using the Delphi approach, this study implemented four phases of data collection using cybersecurity SMEs for proposing and validating OISU: KSAs, KSA measures, KSA measure weights, and cybersecurity competency threshold. A fifth phase of data collection occurred measuring the cybersecurity competency of 54 participants. Phase 1 of this study performed five semi-structured SME interviews before using the Delphi method and anonymous online surveys of 30 cybersecurity SMEs to validate OISU cybersecurity KSAs found in literature and United States government (USG) documents. The results of Phase 1 proposed and validated three OISU cybersecurity abilities, 23 OISU cybersecurity knowledge units (KU), and 22 OISU cybersecurity skill areas (SA). In Phase 2, two rounds of the Delphi method with anonymous online surveys of 15 SMEs were used to propose and validate OISU cybersecurity KSA measures. The results of Phase 2 proposed and validated 90 KSA measures for 47 knowledge topics (KT) and 43 skill tasks (ST). In Phase 3, using the Delphi method with anonymous online surveys, a group of 15 SMEs were used to propose and validate OISU cybersecurity KSA weights. The results of Phase 3 proposed and validated the weights for four knowledge categories (KC) and four skill categories (SC). When Phase 3 was completed, the MyCyberKSAsTM prototype assessment tool was developed using the results of Phases 1-3, and Phase 4 was initiated. In Phase 4, using the Delphi method with anonymous online surveys, a group of 15 SMEs were used to propose and validate an OISU cybersecurity competency threshold (index score) of 80%, which was then integrated into the MyCyberKSAsTM prototype tool. Before initiating Phase 5, the MyCyberKSAsTM prototype tool was fully tested by 10 independent testers to verify the accuracy of data recording by the tool. After testing of the MyCyberKSAsTM prototype tool was completed, Phase 5 of this study was initiated. Phase 5 of this study measured the cybersecurity competency of 54 OISUs using the MyCyberKSAsTM prototype tool. Upon completion of Phase 5, data analysis of the cybersecurity competency results of the 54 OISUs was conducted. Data analysis was conducted in Phase 5 by computing levels of dispersion and one-way analysis of variance (ANOVA). The results of the ANOVA data analysis from Phase 5 revealed that annual cybersecurity training and job function are significant, showing differences in OISU cybersecurity competency. Additionally, ANOVA data analysis from Phase 5 showed that age, cybersecurity certification, gender, and time with company were not significant thus showing no difference in OISU cybersecurity competency. The results of this research study were validated by SMEs as well as the MyCyberKSAsTM prototype tool; and proved that the tool is capable of assessing the cybersecurity competency of an OISU. The ability for organizations to measure the cybersecurity competency of OISUs is critical to lowering risks that could be exploited by cyber threats. Moreover, the ability for organizations to continually measure the cybersecurity competency of OISUs is critical for assessing workforce susceptibility to emerging cyber threats. Furthermore, the ability for organizations to measure the cybersecurity competency of OISUs allows organizations to identify specific weaknesses of OISUs that may require additional training or supervision, thus lowering risks of being exploited by cyber threats.