Summary• The role of flavonoids in mechanisms of acclimation to high solar radiation was analysed in Ligustrum vulgare and Phillyrea latifolia , two Mediterranean shrubs that have the same flavonoid composition but differ strikingly in their leaf morphoanatomical traits.• In plants exposed to 12 or 100% solar radiation, measurements were made for surface morphology and leaf anatomy; optical properties, photosynthetic pigments, and photosystem II efficiency; antioxidant enzymes, lipid peroxidation and phenylalanine ammonia lyase; synthesis of hydroxycinnamates and flavonoids; and the tissue-specific distribution of flavonoid aglycones and ortho-dihydroxylated B-ring flavonoid glycosides.• A denser indumentum of glandular trichomes, coupled with both a thicker cuticle and a larger amount of cuticular flavonoids, allowed P. latifolia to prevent highly damaging solar wavelengths from reaching sensitive targets to a greater degree than L. vulgare . Antioxidant enzymes in P. latifolia were also more effective in countering light-induced oxidative load than those in L. vulgare . Consistently, light-induced accumulation of flavonoids in L. vulgare , particularly ortho-dihydroxylated flavonoids in the leaf mesophyll, greatly exceeded that in P. latifolia .• We conclude that the accumulation of flavonoid glycosides associated with high solar radiation-induced oxidative stress and, hence, biosynthesis of flavonoids appear to be unrelated to 'tolerance' to high solar radiation in the species examined.