DTSGUI is a public-domain software tool to import, manage, parse/cull, georeference, analyze and visualize fiber-optic distributed temperature sensor (FO-DTS) data. Visualization can efficiently be accomplished in the form of heat maps of temperature (as color) versus distance and time, and in map view plots of georeferenced data on land-surface orthoimagery. The code is written in object-oriented Python to facilitate future extension. Data analysis is implemented using tools from the Python libraries NumPy and SciPy, and the graphical user interface (GUI) is implemented using the Python library wx. DTSGUI imports FO-DTS data in two common formats along with spatial coordinates of the FO-DTS cables, plots data and summary statistics (e.g., standard deviation, mean, minimum, maximum) in space and time, and overlays data spatially on maps.