Phenolic compounds in the leaves of 104 blueberry cultivars were investigated using HPLC–DAD and HPLC–ESI–MS² analysis. This approach identified 28 constituents, among which eight constituents were identified certainly by authentic standards, while others were tentative. Three anthocyanins, four flavonols and four chlorogenic acids were reported for the first time in blueberry leaves. Furthermore, the antioxidant activity of blueberry leaves was estimated by using DPPH^•, ABTS^•+ and FRAP assays. It was found that most rabbiteye blueberry cultivars had higher antioxidant activity than most northern and southern highbush ones. The rabbiteye cultivars ‘Vernon’, ‘Britewell’ and ‘T-172, Festival’ appear to be good sources of antioxidants. Hierarchical cluster analysis classified 104 cultivars into three clusters, and they were distinct from each other. This study contributes to current knowledge on the composition of phenolic compounds in blueberry leaves, and identifies specific cultivars which may be potential resources for tea making and food additive.