The release of photoactive halogen species such as Br2 from sea-salt particles, snowpack, and sea-ice can have significant effects on chemistry in the marine boundary layer (MBL). Although the reaction of hydroperoxyl radical (HO2•) with dibromide radical anion (•Br2-) might be a key step in the formation and release of Br2, there is currently no consensus on whether this reaction produces bromide (Br-) or molecular bromine (Br2). To address this question, we measured the formation of gaseous and aqueous oxidized bromide (primarily Br2) in illuminated bromide solutions as a function of pH. Results from these two sets of experimental data are best explained by kinetic models where HO2• oxidizes •Br2- to Br2. Using this reaction in a simple aerosol model reveals that the hydroxyl radical-induced oxidation of particulate bromide, followed by reaction of •Br2- with HO2•, could be an important source of Br2 in the MBL.