This mix-method research attempts at extending our knowledge about the impact of L1 glossing (Persian) for abstract words on reading comprehension in English. It also examines learners' attitudes towards abstract glossed words while engaged in reading. Sixty students in Iranian language institutes were recruited to participate in the quantitative part of the study. Twenty participants from those who involved in the first phase were interviewed in the qualitative part of the study. In the quantitative phase of the study, the participants were placed into control and experimental groups. They were taught for eight sessions. The participants in the control groups had access to L2 glosses (English) for abstract words whereas the participants in the experimental groups were provided with L1 glosses. Using T-test the data were analyzed. The quantitative findings revealed that those who read L1 (Persian) glossed texts outperformed their counterparts who received L2 glosses in reading comprehension. The qualitative showed that participants held a positive attitude towards L1 glosses for abstract words. This attitude was associated with lack of ability in predicting the meaning of abstract words and reinforced by the word-by-word decoding strategy for reading comprehension and time limitation.The implications of the study are discussed.