The main purpose of this study is to critically review research on North Korean English textbooks which was published in South Korea during the past 20 years (1994-2013). For this purpose, a total of 20 research papers and masters theses were chosen for review which directly analyzed either a whole set of North Korean English textbooks or a part of them. The findings are as follows: first, although there was almost a twofold increase in the number of studies during the second half of the research period (2004-2013), most of the studies were masters theses with only 5 research papers published in academic journals. Second, since the year 2000, many more North Korean English textbooks, including a whole set of 6th grade texts, have been available to researchers. However, there still exist difficulties in accessing those textbooks, particularly recently published ones, resulting in limited research in this area. Third, most of the researchers analyzed textbooks in both quantitative and qualitative ways. This is particularly notable in the studies which compare North Korean textbooks with those of South Korea. The validity of the research methods in some studies, however, was not checked. Some suggestions and implications for future research are made relating to these findings.