This study aims to examine how topic familiarity and language proficiency impact the quality of English writing in EFL settings. For the study 64 college freshmen participated, and they were divided into two proficiency groups (high and intermediate). They were asked to write an argumentative essay for two topics each, followed by rating each topic’s degree of familiarity of on a 10-point Likert scale. They were also asked to respond to a questionnaire with two open-ended questions. The results are as follows: 1) participants were more familiar with the driving topic than the smoking topic; however, the differences in their knowledge about these two topics are not likely to come from their different language proficiency; 2) their topical knowledge failed to demonstrate any differences in their writing quality depending upon their language proficiency; and 3) most participants reported that the smoking topic was more difficult to write about, and they believed that both topics would be easier to write about if they did so in their mother tongue. (Chungnam National University · Korea Air Force Academy)