Significance Recent studies have shown that actin-binding and -regulating proteins, originally characterized in the context of cytoskeletal events, can also modify gene expression through directly impacting actin-dependent transcription. This study shows α-catenin (α-cat), an actin-binding protein that is essential for cell–cell adhesion and contact-dependent growth inhibition, can antagonize Wnt/β-catenin–mediated transcription and impact nuclear actin properties, suggesting that these events may be related. These findings establish α-cat as one of a growing list of actin-binding proteins that can modulate transcription, possibly by controlling actin dynamics in the nucleus.