Adaptation in human societies requires dogs to pay attention to socially relevant human beings, in contexts that may greatly vary in social complexity. In turn, such selective attention may depend on the dog’s training and involvement in specific activities. Therefore, we recruited untrained pet dogs (N = 32), dogs trained for agility (N = 32) and for animal assisted interventions (N = 32) to investigate differences in attention to the owner in relation to the dogs’ training/working experience. Average gaze length and frequency of gaze shifting towards the owner were measured in a ‘baseline attention test’, where dogs were exposed to the owner walking in and out of the experimental room and in a ‘selective attention test’, where the owner’s movements were mirrored by an unfamiliar figurant. In baseline, gazes to the owner by assistance dogs were longer than gazes by untrained dogs, which were longer than gazes by agility dogs. The latter shifted gaze to the owner more frequently than assistance and untrained dogs. In the selective attention test, assistance dogs showed longer and less frequent gazes towards the owner than untrained dogs, with intermediate values for agility dogs. Correlations were found for gaze length between the baseline and selective attention test for untrained and assistance dogs, but not for agility dogs. Therefore, dogs trained for Animal Assisted Interventions express enhanced sustained attention to their owners, and the lack of similar effects in agility dogs suggests that involvement in specific activities is associated with large differences in the patterns of attention paid by dogs to their handler/owner.