Although it is infrequent and pedagogically challenging to plan and perform vocabulary instruction, it must be recognized as one of the most important teaching areas in second language (L2) teaching by school authorities, teachers and perhaps students as well. Vocabulary as a teaching area does receive attention both in the syllabus of the English subject and in English as second language (ESL) classrooms. However, the syllabus does not mention how it can be approached. This research synthesis focuses on principles that can guide vocabulary instruction in the ESL-classroom. Through a systematic search process, we found that there is a scale of explicitness and implicitness. The majority of the studies (Al M’tassim & Al-Darayseh, 2014; Mewald, 2015; Sonbul & Schmitt; Lee& Muncie, 2006; Zhao, 2009) tested explicit pedagogical ways in contrast to the traditional implicit ones and came to the conclusion that a combination of both had the most effective outcomes in terms of vocabulary learning. By suggesting teaching principles and discussing them in relation to the syllabus for English 5, we want to illustrate possibilities for a larger focus on vocabulary teaching in the Swedish school.