Dogs that have been rescued, relocated, or have lived in animal shelters could suffer from high levels of stress. The effect that this can have on their behaviour and cognition long-term has not been thoroughly studied. This study investigated possible underlying cognitive impairment that might lead to differences in behaviour between rescue dogs and non-rescue dogs using a series of cognitive tests. These tests were simple enough that they could be performed by owners in their own homes, therefore, citizen science was used to collect behavioural data on rescue dogs (n = 30) and non-rescue dogs (n = 20). Owners of the dogs were also required to complete questionnaires to assess the dog/owner relationship and personality of the dog. Results revealed that rescue dogs showed some possible signs of cognitive impairment compared with non-rescued dogs, particularly in their ability to maintain eye contact with their owner, performing significantly worse than control dogs in an eye contact test (U = 162.5,  p =0.029). However, they performed significantly better than control dogs in a simple memory test (X2(1, N = 40) = 4.404, p = 0.036). Hence, there might be some cognitive differences between rescue dogs and non-rescue dogs and citizen science may be a viable method to collect behavioural data on rescue dogs after they are rehomed.