Corpus callosum (CC) might be related to cognitive performance because of its role in interhemispheric communication. Previous research has focused mainly on volumetric analyses of the CC, yielding contradictory results to some extent. Shape is an approach that integrates and extends the data obtained with the volumetric methodology. Here, we analyze the relationships between midsagittal CC shape variation and several cognitive measures. 2D coordinates from 102 MRI-scanned young adult human CCs were superimposed through a Procrustes approach. The residual variation was regressed onto 21 cognitive measures completed by the participants. Most of these measures (including general intelligence, working memory, executive functioning, and mental speed) were unrelated to midsagittal CC morphology. However, attentional control did show consistent and significant correlations with CC shape variation. Slower responses in attentional control were systematically associated with more curved and thinner CC, with consequent rotation of the splenium and the genu. Although the magnitude of the correlations suggests a small relationship of midsagittal CC geometry and attention, the results provide interesting clues regarding the links between brain anatomical configuration and human cognitive function.