The role of midbrain dopamine neurons in signalling reward prediction is well established, but it is becoming increasingly evident that these signals are heterogeneous. This raises the possibility that dopamine signalling during reward-seeking may vary in different striatal regions. We therefore examined dopamine signalling in the nucleus accumbens (NAc), dorsolateral striatum (DLS) or dorsomedial striatum (DMS) during choice and reward. We developed a mouse decision-making task and measured dopamine signals using fiber photometry. We expressed the GCaMP6f calcium sensor in the ventral tegmental area (VTA) of 2–3-month DAT-Cre mice. Mice were then implanted with an optic fiber in either the VTA, NAc, DLS or DMS. An odour cue was delivered to indicate the start of the decision-making window, during which head-fixed mice could choose to lick either the right or left spout. One spout delivered small, reliable rewards and the other large, rare rewards, with the 2 options counterbalanced across sessions. We observed different signals when a choice had been made and when large vs small rewards were delivered. Furthermore, we observed differences in the activity of dopamine axons across all striatal regions whilst mice performed our decision-making task. Taken together, this suggests that populations of dopamine neurons projecting to distinct striatal areas may encode different aspects of the decision-making process.