Abstract: Cannula retainers for use with oxygen delivery cannulas having a tubular nose piece for introducing oxygen into a person's nose, dependent oxygen tubes extending from opposite ends thereof for looping over the person's ears and which terminate at a connector for connection to an main oxygen delivery tube, and a slidable retaining collar for tensioning the oxygen tubes against the person's lower jaw. The cannula retainers comprise a tubular, band, or elastic body having a hook, clip, loop, or tubular member connected to each end of the body for attachment to the upper and lower portions of the oxygen tube to retain the oxygen tube in a looped configuration about the person's ear. The cannula retainers can be of a fixed length or of a variable length such as being stretchable or elastic, or of an adjustable length. Cannula with retainer assemblies include any of the cannula retainers of the invention with such cannulas.