Research on summer learning has shown that children from a higher socioeconomic status (SES) continue to learn during the summer months of elementary school, but lower-SES students tend to stagnate or lose ground. However, not all low-SES students experience summer learning loss. Drawing on the Beginning School Study (BSS), a longitudinal study of a random sample of Baltimore public school students who began first grade in 1982, this article identifies a small sample of low-SES students who gained as much as their higher-SES peers in reading or math during at least three of the four summers of elementary school. Drawing on Coleman and Hoffer's (1987) theory of within-family social capital, we identify parental characteristics and practices that set these low-SES exceptional summer learners (ESLs) apart from their low-SES peers, who evidence the more typical pattern of summer slide. (Contains 1 figure, 7 tables, and 3 footnotes.)