The Reformed doctrine of definite (or limited) atonement — the 'L' in TULIP — holds that Christ's atoning work was specifically intended and effectively secured for the elect alone. The Canons of Dort (Second Head, Articles 8–9) teach that Christ's death is of infinite value and worth (sufficient for all) but was designed by God to redeem only those whom the Father gave to the Son (efficient for the elect). This stands in contrast to the Arminian view that Christ died for all people without distinction and in contrast to the Lutheran view of universal atonement.

Reformed theologians argue that definite atonement follows logically from unconditional election and ensures that Christ's atoning work is not merely a possibility of salvation for all but an accomplishment of salvation for the elect. The Heidelberg Catechism (Q&A 37) and the Westminster Confession (Chapter VIII) affirm that Christ offered himself to 'satisfy divine justice' and 'reconcile all those given to him by the Father.' Multiple models of atonement — penal substitution, propitiation, reconciliation — are employed in Reformed theology, all understood as securing an effective redemption for the definite company of the elect.