Threshold concepts can be used to both organize disciplinaryknowledge and explain why students have diculties at cer-tain points in the curriculum. Threshold concepts transforma student's view of the discipline; before being learned, theycan block a student's progress.In this paper, we propose that in computing, skills, inaddition to concepts, can sometimes be thresholds. Somestudents report nding skills more dicult than concepts.We discuss some computing skills that may be thresholdsand compare threshold skills and threshold concepts.