The aim of this research is to examine the effect of web-based e-portfolio assessment supported instruction on the knowledge, skills and attitudes of secondary school students in a physical education lessons. This study was designed with a quasi-experimental research model with pretest-posttest control group. The study group of the research consisted of 102 students who were continuing their education in three sixth-grade classes of a middle school in Turkey.  Before the study, the classrooms were randomly assigned as control (teacher evaluation group, N=33), experimental I (portfolio evaluation group, N=35) and experimental II group (web-based e-portfolio group, N=34).  In the research, physical education lessons where basketball was central to the instruction were taught to the control and experimental groups for six weeks. Teacher assessment supported instruction was given to the control group, portfolio assessment supported instruction to the experimental I group, and web-based e-portfolio assessment supported instruction to the experimental II group. In the study, students were tested twice with pre- and post-teaching measurement tools. In the study, basketball achievement test was used to measure the basketball knowledge level of the students, skill rating scales to measure basketball skill level, and physical education lesson attitude scale to measure the attitude level towards the physical education lesson. Obtained data were analyzed with factorial ANOVA test for repeated measurements. The findings of the study demonstrated that the post-test knowledge, skills and attitude scores of the control, experiment I and experiment II groups were significantly higher than the pre-test scores. In addition, it was determined that both the basketball knowledge and basketball skill scores of the experimental I and the experimental II group were significantly higher than the control group in the study. As a result of this research, it can be said that both portfolio assessment supported teaching and web-based e-portfolio assessment supported teaching in physical education lessons are effective in improving students' basketball knowledge and skills.

Web based e-portfolio, assessment, student achievement, skill, attitude.