Listening is one of the most important skills in English language learning. When students listen to English language, they face a lot of listening difficulties. Students have critical difficulties in listening comprehension because universities and schools pay more attention to writing, reading, and vocabulary. Listening is not an important part of many course books and most teachers do not pay attention to this important skill in their classes. In this paper, the researchers reviewed the terms listening, listening comprehension, listening comprehension strategies, and listening difficulties. The review of literature indicated that when teachers are aware of students' learning difficulties they can help them develop effective listening strategies and finally solve their difficulties in listening and improve their listening comprehension abilities.