As an attempt to shed more light on the role of flipped instruction in influencing second language learning outcomes, the present study investigated the impact of flipping the classroom for an English-as-a-Foreign-Language (EFL) writing course on Iranian students’ writing performance and writing motivation. In so doing, two intact classes were selected as the participants (N=43) of the study and they were randomly assigned to the Control Group (N = 18) and the Experimental Group (N = 25). Over a period of one semester, the Control Group was taught using traditional writing instruction, whereas the Experimental Group was taught in a flipped learning mode. Second Language Writing Motivation Scale (SLWMS) and two timed writing tasks were administered to collect the data. The results revealed that the flipped writing instruction significantly contributed to improving L2 writing performance of the experimental group. Also, the results indicated that the flipped instruction had a statistically significant impact on learners’ writing motivation. The findings have significant implications for theory and practice in L2 writing instruction.