In an attempt to investigate the impact of planning on second language (L2) oral production, an experimental study that contrasted the effects of two types of pre-task planning (strategic planning vs. rehearsal) on the L2 oral task performance of 64 Japanese university EFL learners under different modality (aural vs. written) and language (L1 vs. L2) conditions of pre-task input was conducted. The main aim was to determine whether strategic planning (i.e., silent preparation) and rehearsal (i.e., active practice) before L2 oral tasks differentially impact performance in terms of fluency, complexity, and accuracy. An additional aim was to examine the effects on performance of providing pre-task input to assist planning. Furthermore, I elicited the learners’ perceptions of the value of the pre-task input toward assisting their oral task performance via 5-point Likert scale post-task questionnaires. No difference was found between strategic planning and rehearsal in their effects on L2 oral task performance regarding fluency, complexity, or accuracy. This result suggests that, when it comes to pre-task planning, L2 teachers can generally have their learners engage in either strategic planning or rehearsal without differentially impacting their task performance. Concerning the provision of pre-task input, the L1 and L2 input induced commensurate levels of fluency and complexity. However, the L2 input led to significantly greater accuracy of oral production than did the L1 input. This finding is important as it suggests that L2 learners can possibly acquire something from the input provided to them in the course of pre-task planning. Moreover, the post-task questionnaire results corroborated this finding as the participants indicated that the L2 input significantly enhanced their accuracy and also helped them use a wider range of vocabulary during the tasks. Thus, if the aim of a teaching or testing situation is oriented toward fluency, the results indicate that it makes no difference whether pre-task input is in learners’ L1 or L2. In contrast, if the aim is oriented toward accuracy, then teachers and testers should provide L2 input in order to facilitate optimal performance. / Language Arts