The hybrid nature of reading-to-write tasks calls for more empirical research on understanding the relationship between L2 reading, writing, and proficiency. This study examines summaries written by 46 Emirati university students, who were asked to write a 150-word summary of an expository text on the topic of "consumerism" during class hours. The summary was assessed based on an analytic rubric. It was also assessed quantitatively in terms of the inclusion of the number of important ideas from the source text, namely, content analysis scores. In addition, the students' language proficiency, reading proficiency, and writing proficiency had already been externally ascertained with their recent IELTS scores. Significantly positive correlations were found between summary scores and IELTS reading scores, IELTS writing scores, and IELTS proficiency scores. Only a significantly positive relationship was found between content analysis scores and IELTS reading scores, but not the IELTS writing scores and IELTS proficiency scores. This implies the importance of enhancing students' reading, writing, and language proficiency to help them write an effective summary, and reading in itself is insufficient in the production of an effective summary.