This study aims to investigate the relationship between two dimensions of vocabulary knowledge, namely size and depth with reading comprehension on EFL learners at Durbete General Secondary School. The participants of this study were 154 grade 11 students (male=72 and female=82) who enrolled in 2013 E.C.by using stratified random sampling. And to investigate the relationship between vocabulary knowledge (size and depth) with reading comprehension three tests were used. These were Vocabulary Level Test (VLT), Word Associate Test (WAT), and Reading Comprehension Test (RCT). The results were analyzed by Pearson correlation product moment and linear regression by using SPSS 21 Software. The results revealed that there was a significant and moderate positive relationship between breadth (size) and reading comprehension (r=0.607, p<.01).It was found that there was a weak positive relationship between vocabulary depth and reading comprehension at a significant level ((r=0.441, p<.01). The result indicates that the vocabulary size was more correlated with reading comprehension than vocabulary depth in this