Purpose: There is limited research on the reasons behind startup failure, and none of the available studies use a competency approach. In this study we applied Spencer’s competency model to identify the competencies in startups which, according to their CEOs, contributed to failure. Methodology: Three coders analyzed the stories of 50 startup failures published online using modified Critical Incident Technique. Findings: Two salient competencies were identified playing a fundamental role in startup failures if missing: Information seeking and Customer service orientation. A network pattern of 9 more prevalent competency deficits was created: Technical/professional/managerial expertise, Analytical thinking, Flexibility, Self-control, Concern for order, quality and accuracy, Interpersonal understanding, Self-confidence, Team leadership and Teamwork and cooperation. Besides startup-specific behavior descriptions were added to Spencer’s competencies. Research implications: Competency approach and Critical Incident Technique method proved to be feasible to identify competency deficits in failed startups. Practical implications: The identified competency deficits offer relevant focus areas for the assessment and development of startup teams. Originality: The study provided research evidence to describe the competency deficits of startup teams that are connected to their failure.