Learning Grammar Skills and EFL Libyan Students’ Errors This research illustrates the different kinds of grammatical issues that could be a problematic to many students. Also, it discusses theories and research relating to second language proficiency, second language performance, and second language knowledge. This research consists of six important headings. Namely, Definitions of English grammar, a historical overview of teaching English grammar, Defining grammatical difficulty in second language learning, Defining implicit and explicit knowledge, Implicit and explicit knowledge and their relationship, role in learning English grammar, The difference between errors and mistakes in English grammar, Factors affecting EFL students learning English grammar, The importance of grammar in English language , common EFL problems in learning grammar and finally, some related previous studies were mentioned. The related studies were combined in logical relations, namely, their similarities and differences on grammatical issues are discussed their similarities and differences on grammatical issues are discussed