Fluorine-doped tin oxide (FTO) is one of the most studied and established materials for transparent electrode applications. However, the syntheses for FTO nanocrystals are currently very limited, especially for stable and well-dispersed colloids. Here, we present the synthesis and detailed characterization of FTO nanocrystals using a colloidal heat-up reaction. High-quality SnO2 quantum dots are synthesized with a tuneable fluorine amount up to ~10% atomic, and their structural, morphological and optical properties are fully characterized. These colloids show composition-dependent optical properties, including the rise of a dopant-induced surface plasmon resonance in the near infrared.