In 2019, excavation in the Yalnızlar neighbourhood of Sinop, Turkey, revealed a small number of architectural remains, two stone-paved floors and two lavishly decorated pebble-mosaic floors. Both the architectural remains and the pebble-mosaic floors are rare finds in Sinop, even more so given that the floors were found largely intact within their architectural settings. These elements appear to have constituted a portion of a once-grand house of the mid-fourth century BC. This article focuses on the pebble-mosaic floors, which will be analysed in two parts. The first introduces the floors and considers their construction techniques and decorative programmes. Analogies form an essential part of the analysis in order to contextualise both pavements within the corpus of Greek pebble-mosaic floors. A holistic evaluation of the architectural remains and the mosaics follows, in order to consider the setting and use of the floors. In the second part of the article, the sociocultural context of the mosaics is addressed. The analysis considers the meaning and symbolism of their decorations, as well as the place they once occupied within the lives of their owners. Ultimately, the position of the examples from Sinope within the wider sphere of mid-fourth-century BC Greek pebble-mosaic floors will be considered, along with the significance of such lavishly decorated floors in Sinope at this time.