The development of critical skills for deputy principals is a matter which deserves attention, owing to the critical role which deputy principals are expected to play in school management. However, this area of research is neglected and has received limited attention in the literature that focuses on school leadership development. In this vein, the critical skills needed by deputy principals should be identified in order to suggest measures or programmes to develop the skills. Moreover, the role of deputy principals in school management and leadership brings expectations which need to be met through effective performance. In order for deputy principals to perform their duties as expected, they need proper skills and professional development. The purpose of the study reported on here was to identify and establish the extent of the need of critical skills for deputy principals in secondary schools. In order to achieve the aim of the study, a quantitative survey was adopted to collect the data. The paradigm used was the post-positivist paradigm. The participants in the study were 157 secondary school deputy principals from one province in South Africa. Data were gathered using a standardised questionnaire and analysed by means of descriptive statistical techniques, including frequencies, means and percentages. The results reveal that deputy principals in the studied sample needed positional-awareness or role-awareness, technical, socialisation and self-awareness skills in order to perform their duties effectively. We recommend a preparation programme, mentoring and ongoing professional development to develop these skills for deputy principals in order to empower them to contribute to the attainment of quality education.