This paper provides an overview of psychological issues relating to siblings of handicapped persons and the actual state of the support system for such issues in Japan. These siblings have been shown to exhibit a variety of socio-psychological problems due to the existence of their handicapped brothers and sisters, such as a sense of isolation, having an excessive burden placed on them relative to their age, and a sense that they will be burdened with caring for their handicapped brothers and sisters in the future. While several factors relating to socio-economic problems have been reported such as gender, birth order and other sibling attributes, the type and extent of the handicap, and the attitude that parents have toward their handicapped children, no consistent insight into the subject has thus far been gained. Additionally, the practice of support for handicapped persons and their families as well as for their siblings has gradually been established in Japan. This support commonly takes the form of recreational activities and group work, and is expected to have positive outcomes. Research on siblings of handicapped persons is still emerging, and systematic, practical research controlling for socio-psychological factors to an extent is necessary. Psychological assistance and a sociopsychological approach should be taken toward sibling support while taking into account the individuality and development level of each person after properly identifying the needs of each family and individual. These are some of the issues that must be addressed in the future.