Alternative assessment in education is becoming widely implemented around the Pacific region. This study conducted a multilevel analysis of communication climate and beliefs about the effectiveness of alternative assessment. Participants were 662 teachers from 75 elementary schools in Korea. The findings showed that teachers' beliefs about the effectiveness of alternative assessment were positively influenced by their perception of communication climate at their schools and their perception of support from principals, peer teachers, students and parents. The effect of teachers' endorsement of textbook-based learning was moderated by school-level communication climate. The findings indicated that an open communication climate at schools is a key for the successful implementation of alternative assessment.