Background: Research studies (e.g., Phakiti, Language Testing 25(2):237-272, 2008a; Phakiti, Language Assessment Quarterly 5(1): 20-42, 2008b; Purpura, Learner strategy use and performance on language tests: a structural equation modeling approach, 1999) conducted on the construct validation of Bachman and Palmer's (1996) strategic competencehas been quantitative in nature. Furthermore, the nature of Bachman and Palmer's (1996) strategic competence model with regard to graph-writing has remained unexplored. Methods: The present study aimed at investigating the validity of the strategic competence model comprising of three components namely goal setting, assessment, and planning through grounded theory approach. To do so, 8 English Language students participated in this study during 10 weeks. They completed GPT task while thinking aloud their writing processes. Then, their retrospective interview protocols were collected. Observations of the students engaged in writing GPT were conducted, and writing samples from each student were provided by the observers. Qualitative analysis program, NVivo 10 imported, transcribed, summarized, and visualized the data. Consistent with constructivist grounded theory approach, the data were analyzed by initial coding, focused coding, axial coding, and theoretical coding. Results: The model that explained the processes of this task included five major. These processes involved "Analyzing Non-Graphic Information of Instruction", "Translating Graphic and Non-Graphic Information into Written Discourse", "Retrieving Personal Interpretation and Additional Reasoning", "Evaluating Graph Comprehension", and "Reformulating Graph Description into EFL Written Discourse." Conclusion: This model yielded the recursive nature of the core processes in relation to different components of strategic competence and its credibility through data triangulation. Methodologically, such findings highlight the importance of considering test takers cognitive processes when designing and developing graph writing tasks.