The idea of students as authors of assessment items, in particular, multiple-choice questions, is being increasingly taken up by classroom teachers, and studies examining its educational potential have largely been positive. A concomitant question regarding if and how students benefit from the use of student-authored questions with answers and explanations for learning is currently understudied. Noting that the structures, types, and amount of knowledge between a teacher and students may be distinctly different, the purpose of this study was to examine whether there are different learning effects from the use of student- versus teacher-generated explanations for answers to online multiple-choice questions. Additionally, an attempt was made to determine the ways that explanations generated by students and teachers differ. A non-equivalent pretest-posttest experimental research design was adopted. Four sixth-grade classes (n = 104) from a single primary school participated in six weekly online multiple-choice question-answering exercises. Although the results of the analysis of covariance did not show statistically significant between-group differences in academic achievement, the participants receiving student-generated explanations had significantly better attitudes toward the subject matter as compared to their counterparts receiving teacher-generated explanations. A content analysis on the explanations generated by the teacher and students, followed up by chi-square tests of independence, post-hoc pairwise tests with Bonferroni correction, and t-tests further revealed significant differences in several areas, including types of explanations, styles, and number of words.