The present inquiry inspected the impact of metacognitive awareness on the fluency of 114 Iranian TEFL learners' task-based oral output. The participants in six intact classes were selected from a population of 120 English sophomores based on their scores on proficiency pre-test. The classes were randomly assigned as two tripartite groups of experimental and control participants each embracing three groups of pre-task planners (PTP), on-line task planners (OLP), and pre and on-line task planners (POLP). The fifteen-session metacognitive awareness program in the form of a topic-based listening and speaking course was based on Cotterall's (2000) principles of autonomous learning and three sets of metacognitive strategies, centering learning, arranging and planning learning and evaluating learning (Oxford, 1990). Employing a narrative task type, the researcher collected the data using a 2x3 factorial design with two levels of metacognitive awareness and three levels of planning. It was hypothesized that fluency would improve through metacognitive awareness under various planning conditions. Two-way Repeated Measures and One-way ANOVA analyses of the research data revealed significant fluency gains in all experimental participants compared to the control ones and in the control POLP planners. The findings have pedagogical implications for educators and teachers and highlight the need for strategic investment.