This study investigated the effects of virtual and physical laboratory instruction on the retention of electrical circuits concepts among National Diploma (ND) II Electrical Engineering students in polytechnics in North-East Nigeria. A pre-test, post-test non-equivalent group quasi-experimental design was employed, involving 194 students from four polytechnics, with 89 students in the virtual laboratory group and 105 in the physical laboratory group. Data were collected using a validated 50-item multiple-choice Electric Circuits Academic Performance Test (ECAPT), administered as pre-test, post-test, and retention test. Results indicated that students taught using the virtual laboratory demonstrated significantly higher retention scores ( = 70.35) compared to those taught in the physical laboratory ( = 61.46). Male students showed a slight advantage in retention, but the interaction between teaching method and gender was not statistically significant, suggesting that both genders benefited comparably from virtual laboratory instruction. The findings highlight the efficacy of virtual laboratories in enhancing long-term retention of electrical engineering concepts and support their integration as a cost-effective and equitable supplement to traditional hands-on laboratory instruction in polytechnic education.

Keywords: Virtual Laboratory, Physical Laboratory, Retention, Electrical Circuits, Polytechnic Students, Electrical Engineering.