The hydroperoxy radical (HOO•) plays a critical role in Earth's atmospheric chemistry as a component of many important reactions. The self-reaction of HOO• forms HOOH, which is an important oxidant in atmospheric chemistry. The reaction of HOO• with organic peroxy radicals (ROO•) is an important reaction in regions of the lower atmosphere that are minimally affected by anthropogenic combustion. In this work we explore the hydrogen bonding interactions of a pair of hydroperoxy radicals and the reactions leading to production of HOOH. We also examine the reaction of HOO• with HOCH₂CH₂OO•, including hydrogen bonded complexes of these two radicals. The HOCH₂CH₂OO• radical is the model for peroxy radicals derived from alkenes, and this work is a stepping stone towards understanding the interactions and reactions of the eight isomeric isoprene-OH peroxy radicals with HOO•. Density functional methods significantly underestimate the most critical activation barrier on the HOO• + HOO• potential energy surface, but provide good structures for single point calculations at CCSD(T).