The study is aimed at investigating 1) the level of computer self-efficacy among public senior high school (SHS) teachers in Ghana and 2) the functionality of teachers' age, gender, and computer experiences on their computer self-efficacy. Four hundred and Seven (407) SHS teachers were used for the study. The "Computer Self-Efficacy" (CSE) scale, developed by Teo and Koh (2010) was adapted and used for data collection. Descriptive statistics, "t" tests and univariate analyses were employed to analyse the data. The results showed that generally, SHS teachers neither disagree nor agree that they are computer self-efficacious; specifically they agree that they are self-efficacious in basic computer skills but not certain about their self-efficacy in web based skills and not self-efficacious in media related computer skills. Moreover, the results revealed that teachers' age, gender, and computer experiences have similar and dissimilar influences on their computer self-efficacy related to different computer application software. Furthermore, according to the results, teachers' gender and their computer experience have interaction effect on their computer self-efficacy whilst 1) teachers' gender and age and 2) teachers' age and computer experience have no statistically significant interaction effect on their computer self-efficacy. The study provides new and vital information for educational practitioners in Ghana. The findings suggest that expecting teachers in developing country such as Ghana to teach with technology still remains as a very challenging issue which requires important attention. In addition, the study provides new insights into explanation for contradictory research findings of the effect of (SHS) teachers' age, gender, and computer experience on their computer self-efficacy in the literature.