This study examined the effects of a teacher-delivered intervention with online mathematics mini-games on special education students' multiplicative reasoning ability (multiplication and division). The games involved declarative, procedural, as well as conceptual knowledge of multiplicative relations, and were accompanied with teacher-led lessons and class discussions. A pretest-posttest control-group design was employed, with 81 students from five schools for special primary education (three experimental schools and two control schools). The intervention consisted of two 10-week game periods in which a total of 16 mini-games were offered as part of the regular educational program for multiplicative reasoning. The control group students played non-multiplicative mini-games; for multiplicative reasoning, they followed their regular educational program without mini-games. In both groups, students' multiplicative reasoning ability significantly increased. Regarding declarative knowledge of multiplication facts, learning outcomes were significantly higher in the experimental group as compared with the control group. This finding indicates the usefulness of mini-games for enhancing special education students' mathematics fact knowledge. Learning outcomes on a test measuring procedural and conceptual knowledge of multiplicative reasoning did not differ between experimental and control group. For these learning outcomes, then, the mini-games intervention did not have added value but can still be considered a "safe" alternative approach.