JISE 12 (3) (2023): 262-268 Journal of Innovative Science Education http://journal.unnes.ac.id/sju/index.php/jise Pre-Service Teachers’ Conceptual Understanding and Retention When Taught Osmosis Using Group Discussions Israel Kibirige  University of Limpopo, South Africa Article Info Article History : June 2023 Accepted August 2023 Published December 2023 Keywords: Pre-service teachers; au- thentic experiments; conceptual understanding and retention; Group dis- cussion; traditional approach. Abstract Group Discussion (GD) as a collaborative teaching strategy focuses on the teachers and learners to solve problems through multiple engagements. The purpose of the study was to determine the effect of GD on pre-service teachers’ conceptual understanding and retention compared to the Traditional Approach (TA) in teaching osmosis. A quasi-experimental design with pre-and post-tests and a case study design were used for the study. Ninety-four pre-service teachers (N=47) for the Experimental Group (EG) taught using GD, and (N=47) for the Control Group (CG) were taught using the Traditional Approach (TA). Results from post-tests show EG performed better than CG, as indicated by Analysis of Covariance (ANCOVA), p < .05, suggesting that GD improved conceptual understanding. A Mann-Whitney U-test shows no significant differences in performance between males and females in EG, implying GD favoured both genders. In addition, EG retention was higher than CG when tested after an extended period. Thus, the results show that GD improves pre-service teachers’ conceptual understanding and retention. The implication for educators is that the use of GD in teaching biology improves pre-service teachers’ conceptual understanding of Osmosis, and these results have far-reaching implications in teacher education.  correspondence : Polokwane, 0727, South Africa E-mail: israel.kibirige@ul.ac.za p-ISSN 2252-6412 e-ISSN 2502-4523