We present an investigation of the plasmon excitations in a quasi-one-dimensional metal, the blue bronze K 0.3 MoO 3 . The dispersion relation along the one-dimensional direction, as measured by electron energy-loss spectroscopy in transmission, is quasilinear over a wide momentum range before it exhibits a negative curvature. We show that the quasilinear part can be explained within an essentially three-dimensional model based on the random-phase approximation. Band-structure effects are thereby considered through the Ehrenreich-Cohen formula, tailor-made to the specific, strongly anisotropic material. From this analysis, we find no hint for exceptional properties caused by one dimensionality as is currently discussed in the context of photoemission measurements. The genuine dependence of the plasmon modes on the propagation angle relative to the one-dimensional axis is masked by interband transitions lying at about the same energy as the plasmon excitations itself.