This paper examines the influence of contemporary rhetoric on John Chrysostom's commentary on Galatians (with some reference to other exegetical works). Because ancient rhetoric developed over time, the primary points of reference are works on rhetorical theory, commentaries on Demosthenes and rhetorical exercises dating to the second century ce and later. It is argued that modern attempts to classify the letter under the three standard classes of oratory are misconceived in terms of ancient theory, but that this is not an obstacle to rhetorical analysis. John's use of rhetorical concepts in analysing the structure of the letter is illustrated, as is his use of the pattern of counterposition (an objection attributed to an opponent) and solution, both as a compositional device and as an exegetical tool. In his interpretation of Gal. 2:1-10, John argues Paul is unable to deal fully with counterpositions because of the constraints entailed by a covert strategy agreed by the apostles at the Jerusalem consultation. John's interpretation of the confrontation with Peter at Antioch, according to which Peter pretended to give way to Paul's opponents in order to give him an opportunity to respond, is shown to be based on the rhetorical concept of figured speech. John's attention to Paul's management of the relationship with his addressees is examined. The admiration which John expresses for this and other aspects of Paul's rhetorical technique is shown to echo, in content and phrasing, similar expressions of admiration in commentaries on Demosthenes originating in contemporary rhetorical schools.