While schools play a major role in promoting parental involvement in schooling in many countries, few comparative studies examined the level of school expectation for parental involvement and its effect on student achievement. Using the TIMSS 1999 dataset, this study examined the level of school expectation for various types of parental involvement in the US and South Korea and the relationship among school characteristics, expectations for parental involvement, and 8th grade students' mathematics achievement. The study showed that teacher collaboration and school disorder problems were two school factors associated with the level of school expectations for parental involvement in both countries. The study also found that school expectations for parental involvement were significantly associated with higher student achievement in mathematics in the US but not in South Korea. Policy implications for US schools and South Korean schools are discussed. (Contains 4 tables and 1 figure.)