This study evaluated the impact of a professional development program (PDP) on science lecturers' level of knowledge/understanding and the extent of use of modern technologies for improving their self-efficacy in teaching in the areas of students' engagement, instructional strategies, and classroom management, in some selected universities in Nigeria. The study adopted a descriptive survey design. The sample was 269 lecturers. The researchers adapted the teacher sense of efficacy scale (TSES) developed by Tschannen-Moran and Hoy (2001) for the study. The TSES has two parts (1) and (2) that contained 12 questions each. It was a validated instrument, with overall reliability indices of 0.92 and 0.95 respectively determined using Cronbach’s Alpha. The data obtained were analyzed with mean, standard deviation, and paired sample t-test. The study found that the PDP improved the lecturers' understanding of modern technologies and self-efficacy in teaching (t (268) = 30.959, p = 0.000 ˂ 0.05). Also, the PDP improved the lecturers’ extent of utilisation of modern technologies and self-efficacy in teaching (t (268) = 28.510, p = .000 ˂ .05). The study also found that the lecturers’ understanding of modern technologies after the PDP was high, but their use of modern technologies in teaching was still low. The researchers recommended that science lecturers' participation in PDPs should be regular to improve their understanding and use of modern technologies in teaching for enhanced self-efficacy and sustainable science education in developing nations.