The main purpose of this study is to explore the effects of the use of games as a teaching strategy for raising the grammatical accuracy level of secondary students of German as a second language. This thesis seeks also to examine the effect of game-based grammar instruction on students’ motivation and classroom atmosphere. The participants in this study were divided into two groups, the Control and Experimental groups, and received 90 periods, over 18 weeks, of grammatical instruction by the same teacher. The teaching program was the same for both groups. The difference consisted in the use of game-based practice for the experimental group, while the control group performed traditional grammar-based practice only. Data were collected using the following instruments: grammar tests and examinations,a questionnaire on motivation, a questionnaire on classroom atmosphere, a questionnaire on the type of grammar practice, a questionnaire on the role of grammar and grammar instruction, focus group interviews with students, and the researcher’s field notes. While the main result does not support the hypothesis for significant improvement in grammatical accuracy by the experimental students as a result of game-based practice, their overall improved performance is a worthwhile achievement, particularly if it is linked to significant improvements in students’ motivation and classroom atmosphere.These positive results offer a notable incentive to language teachers to include games in their teaching of grammatical features, because the positive results of this experiment with regard to learners’ motivation, peer interaction, teacher-student interaction augur well for an eventual improvement also in the rate of grammatical accuracy.