The objective of this analysis was to examine the genetic architecture of diverse cognitive abilities in children and adolescents, including the magnitude of common genetic effects and patterns of shared and unique genetic influences. Subjects included 3689 members of the Philadelphia Neurodevelopmental Cohort, a general population sample comprising those aged 8–21 years who completed an extensive battery of cognitive tests. We used genome-wide complex trait analysis to estimate the SNP-based heritability of each domain, as well as the genetic correlation between all domains that showed significant genetic influence. Several of the individual domains suggested strong influence of common genetic variants (for example, reading ability, h2g = 0.43, P=4e-06; emotion identification, h2g = 0.36, P=1e-05; verbal memory, h2g = 0.24, P = 0.005). The genetic correlations highlighted trait domains that are candidates for joint interrogation in future genetic studies (for example, language reasoning and spatial reasoning, r(g) = 0.72, P = 0.007). These results can be used to structure future genetic and neuropsychiatric investigations of diverse cognitive abilities.