Background:　The　potential　applications　of　food-derived　antioxidant　peptides　as　additives,　nutraceuticals　and　therapeutic　agents　have　fueled　current　interests　to　discover　them　from　diverse　plant　sources.　A　growing　number　of　antioxidant　peptides　have　been　identified　from　edible　plant　sources,　as　well　as　plant-based　agricultural　and　food-processing　by-products.　Scope　and　approach:　We　summarized　recent　progress　in　the　research　of　plant-derived　antioxidant　peptides,　particularly　their　biological　effects,　mechanisms,　and　structure-activity　relationship.　Many　studies　assessed　the　potency　of　antioxidant　peptides　by　using　chemical　assays.　However,　the　outcome　of　chemical　methods　may　not　reflect　the　biological　significance.　Thus,　this　review　focusses　on　antioxidant　peptides　whose　effectiveness　was　demonstrated　by　using　cellular　and/or　animal　models.　This　review　pays　particular　attention　to　studies　which　successfully　determined　the　sequences　of　antioxidant　peptides　under　investigation.　Due　to　the　scarcity　of　the　assessment　of　pure　antioxidant　peptides　in　animal　models,　in　vivo　evidence　from　well-characterized　peptide　fractions　or　hydrolysates　will　also　be　discussed.　Key　findings　and　conclusions:　Plant-derived　antioxidant　peptides　diminished　reactive　oxygen　species　production,　besides　activating　endogenous　antioxidant　defenses　in　cellular　models.　Some　such　peptides　exerted　protection　by　modulating　pro-　and　anti-apoptotic　proteins　as　well　as　gene　and　protein　expression　of　antioxidant　enzymes.　By　using　cellular　models,　the　intestinal　absorption　and　metabolism　of　such　peptides　were　elucidated.　Plant　protein　hydrolysates　enhanced　antioxidant　protection　in　animal　models,　often　by　upregulating　antioxidant　enzyme　activities　in　various　body　tissues.　The　structure-activity　relationship　of　plant-derived　antioxidant　peptides　is　not　well-understood.　Nevertheless,　information　connecting　peptide　secondary　structure　to　cellular　antioxidant　effects　has　emerged.　©　2020　Elsevier　Ltd