Abstract: Abstract We investigate multi-boson interference. A Hamiltonian is presented that treats pairs of bosons as a single composite boson. This Hamiltonian allows two pairs of bosons to interact as if they were two single composite bosons. We show that this leads to the composite bosons exhibiting novel interference effects, such as Hong–Ou–Mandel interference. We then investigate generalisations of the formalism to the case of interference between two general composite bosons. Finally, we show how one can realise interference between composite bosons in the two-atom Dicke model. Keywords: interference of bosonsquantum opticsHong–Ou–Mandel effect Acknowledgements We acknowledge financial support from the Doppler Institute and from Grants MSM6840770039 and MSMT LC06002 of the Czech Republic. S.M.B. thanks the Royal Society and the Wolfson Foundation for financial support. Notes Notes 1. Actually there are four paths, however, two of these paths are identical. The indistinguishability of quantum particles means that these two paths should not be viewed as a separate paths.