This study examined longitudinally the effectiveness of some motivational strategies in promoting the L2 motivation of Saudi learners in their EFL classes. The study conducted empirical investigations over two stages. In the first stage, the rank order of the most important strategies was obtained. In the second stage, 296 EFL students were randomly divided into two groups: an experimental group that was exposed to the 10 pre-selected motivational strategies in their classes by seven teachers, and a control group in which another seven teachers followed the traditional way of teaching. Motivation questionnaires as well as classroom observations and teacher post-lesson evaluation protocols were used to assess the teachers'' motivational practices and students'' motivated behaviours in the classroom at the start and the end of the experimental period. The statistical analyses of the collected data clearly showed a significant rise in motivational levels for students in the experimental, but not the control group. This study could be of potential interest and help for researchers in the field of linguistics and second/foreign language acquisition as well as for ESL/EFL teachers.