Motives for writing is a new research area in the field of writing motivation. Recent studies have identified important motives for students' writing. Adding to this nascent foundation, the current study examined relationships between writing motives, writing self-efficacy and time spent on writing using a sample of grade 4 Chinese students in Shanghai (n = 619) who completed a questionnaire assessing these constructs. Four alternative models, driven separately by key motives including social recognition, curiosity, competition and grades, depicted complex relationships between motives, self-efficacy and time on writing. The grades driven model best-fitted the data. This final model showed the importance of grades as a key motive for writing and how intrinsic and extrinsic motivational pathways were originated from this performance-focused motive, connecting with writing self-efficacy and time spent on writing. Cluster analyses classified these Chinese students into seven groups of beginning writers holding contrasting profiles of writing motives. Extremely-motivated and highly-motivated writers held multiple motives in their profiles. The motive profiles of curious and averagely-motivated writers were dominated by curiosity and involvement. Performance-focused and weakly-motivated writers focused predominantly on grades as a key motive. Finally, unmotivated writers did not hold any clear motives for writing. These clusters of writers differed in writing self-efficacy but not in their time spent on writing. Complementing the findings of path analyses, cluster analyses showed grades as a dominant motive for writing among different clusters of motivated writers.