Exemplary embodiments are disclosed of multiport multiband vehicular antenna assemblies. In exemplary embodiments, a multiport multiband antenna assembly may include multiple ports (e.g., three, four, or five ports, etc.) with different combinations of antennas or radiators operable over various frequencies, such as one or more cellular frequencies (e.g., Long Term Evolution (LTE), etc.), internet frequencies (e.g., Wi-Fi, Wi-Fi ISM, etc.), satellite navigation frequencies (e.g., Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), etc.), and/or other frequencies. For example, a multiport multiband antenna assembly may include radiators or antennas operable with LTE, WI-FI, GPS (and/or with other cellular, internet, and/or satellite navigation frequencies) where the radiators or antennas are located and/or part of a single antenna system, e.g., positioned on and/or supported by the same or common base assembly and within the same interior enclosure cooperatively defined by the base assembly and radome of a single roof-mount antenna system, etc.