This study investigated the effects of educational context variables on two types of achievement: cognitive domain and affective domain. To assess the effects of educational context variables at student and school levels, the National Assessment of Educational Achievement data were used, which were collected by the Korea Educational Development Institute. Participants were in the second year of a high school. Multivariate multilevel modeling was employed to model the two related dependent variables: cognitive and affective domains. Results showed that school characteristics were generally more influential for cognitive achievement than for affective achievement. Moreover, it was found that psychological stability and satisfaction with the facilities at school played an important role in predicting affective achievement for the subjects of Korean, English, and mathematics. Korea's Educational Broadcasting System was found to exert a positive effect on affective achievement, but negative effects on cognitive achievement. Shadow education was found to be generally helpful in improving cognitive/affective achievement. Programs aimed at improving academic achievement at school were found to have had very limited success in accomplishing their aim. Teacher climate, in particular, adversely affected students' cognitive achievement. Schools must be equipped with good facilities and counseling centers for student to improve student achievement.