The researcher addressed a research gap in the area of adolescents with a diagnosis of Asperger's Syndrome (AS) and co-morbid depression by investigating the possibility of a relationship between co-morbid depression and the level of social impairment in this population. Through this study, the researcher also attempted to gain an understanding of personal experiences of AS adolescents with and without co-morbid depression. Using a sequential explanatory strategy for mixed methods research, 182 archived records of AS adolescents were analyzed to determine if a relationship existed between the two variables. The results of a point-biserial correlation analysis indicated that there was no significant correlation between the presence of co-morbid depression and the total levels of social impairment found on the Social Responsiveness Scale (SRS) in each archived record of this sample. No correlation was found between the presence of co-morbid depression and aspects of social impairment measured by all five of the subscale components of the SRS: social awareness, social motivation, social communication, social cognition, and autistic mannerisms. Seven SRS test items exhibited statistically significant differences between the means from the two population groups. These seven test items served as the basis for the survey interview questions answered by 50 AS adolescents via SurveyMonkey.com in the qualitative part of the study. Using a thematic analysis, the responses were coded into four common major themes: self-concept, social interactions/interpersonal relationships, Theory of Mind deficits, and depression. A comparison of the responses indicated support for the lack of correlation between social impairment, as measured by the SRS total and SRS subscales, and co-morbid depression. However, a greater percentage of responses from AS adolescents with co-morbid depression that described social impairment issues hint at a positive correlation actually existing between co-morbid depression and social impairment levels in AS adolescents. Research using a social impairment measure administered contemporaneously with the study, rather than extracted from archived records, is needed to explore such a possibility.