The purpose of this study is to review available literature on stress, attachment styles, and cultural differences of American and Korean missionaries. Attachment styles established in one’s early years are relatively stable and affect relationship throughout one’s life, including adulthood. Attachment patterns are especially important for the ways in which adults manage stress in their relational lives. When experiencing stress, those with secure attachment tend to seek out relationships in a balanced, self-confident way. However, those with insecure attachment withdraw from relationships (avoidant attachment), are indifferent to relationships (dismissing attachment), are overly concerned about relationships (preoccupied attachment), or are anxious and fearful about relationships (fearful attachment). For the case of missionaries, they experience separation from their primary attachment figures, their home country, culture, and language. Moreover, missionaries face multiple stressors including culture shock, social and geographical remoteness, restrictions of resources, and relational tensions. Therefore, on the mission field, their internal working model will be more apparent. Regardless of physical, emotional, interpersonal, and spiritual growth, missionaries’ responses to stress are likely to be related to their attachment styles. The cultural differences in attachment styles were discussed. More research on attachment and culture is advocated.