Single-crystal electron diffraction patterns have been obtained from oriented samples of two commercial microcrystalline waxes. Their crystal structures, which are also expressed in oriented samples of pure methyl-branched n-paraffins, reveal a bridged lamellar structure reminiscent of low molecular weight linear polyethylene. An interdigitated lamellar packing is proposed that accommodates the methyl branches and nearby vacancies. A parallel study of n-alkyl derivatives of benzene and cyclohexane, on the other hand, reveal that naphthenic components adapt an oblique layer structure unlike the rectangular layer packing found for the petroleum waxes and the branched alkanes.