Influenza virus-like particles (VLPs) comprising the structural proteins HA, NA, M1 and M2 are described. VLPs are also generated containing M1 alone, as are VLPs with M1 and any one or two of HA, NA and M2. VLPs with HA from one influenza subtype and NA from a different influenza subtype are also described, as are VLPs in which a portion or all of HA or NA is replaced by a heterologous moiety not produced by influenza virus, so as to comprise chimeric VLPs.