Significance Telomerase, which extends DNA at chromosome ends, is composed of an RNA template and a catalytic protein subunit, telomerase reverse transcriptase (TERT). TERT gene expression has been of great interest because it is required for proliferation of most cancers, but expression investigations have been limited due to low endogenous mRNA levels. Here, we employ single-molecule RNA fluorescent in situ hybridization (FISH) in 10 human cancer cell lines and make findings that are unanticipated based upon bulk TERT mRNA measurements. For example, there is great cell-to-cell variation in the number of transcription sites, and spliced TERT mRNA has greater nuclear localization than cytoplasmic. Overall, our findings provide insights regarding TERT expression, localization patterns, and variability in cancer on a single-cell level.