This study examined loneliness, social support, and help-seeking behavior in children, ages 9 to 13. Participating were 330 fourth to sixth graders from middle and low income families from the Montreal, Canada region, who completed two questionnaires measuring feelings of loneliness and social dissatisfaction and help-seeking. Independent variables were sex, school performance, and socioeconomic status (SES). The results indicated that children with lower school performance were significantly more lonely than children with higher school performance, and more particularly expressed feelings of rejection and isolation. Sex and SES had no effect on the loneliness score. However, the presence of social support and help-seeking behavior were influenced particularly by sex and school performance, and to a lesser degree, by SES. Girls sought help more than boys for all the problem situations encountered and sought more often the emotional and information type of support during which they appealed to the nuclear family and to friends. Low-performing children on the whole sought as much help as high-performing children, except for two emotional situations related to confiding a problem in someone and when the child was sad. Sex, school performance, and SES also determined the relative importance of different sources of support, nuclear family, extended family, friends, and animals. The nuclear family was sought out first for informational support, before emotional support. (Contains 25 references.) (KDFB)