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Epsilon-near-zero (ENZ) media are an emerging class of nanophotonic materials that engender electromagnetic fields with small phase variation due to their approximately zero permittivity. These quasi-static fields facilitate several unique optical properties, such as subwavelength confinement, arbitrary wavefront control, and enhanced light–matter interactions, which make ENZ materials promising platforms for nanophotonic and plasmonic systems. Here, we report our analysis of single and dimer nanoantennas deposited on an aluminum-doped zinc oxide layer with an ENZ wavelength around 1.5 μm. Using near-field microscopy, far-field spectroscopy, finite-element numerical simulations, and a semi-analytic Fabry–Perot (FP) model, we show that single nanoantennas support highly dispersive plasmonic modes with less than unity effective mode index at wavelengths greater than the ENZ wavelength, which …