Inaccurate perception of respiratory symptoms is often found in asthma patients. Typically, patients who inaccurately perceive asthma symptoms are divided into underperceivers and overperceivers. In this paper we point out that this division is problematic. We argue that little evidence exists for a trait-like stability of under- and overperception and that accuracy of respiratory symptom perception is highly variable within persons and strongly influenced by contextual information. Particularly, expectancy and affective cues appear to have a powerful influence on symptom accuracy. Based on these findings and incorporating recent work on associative learning, attention and mental representations in anxiety and symptom perception, we propose a cognitive-affective model of symptom perception in asthma. The model can act as a framework to understand both normal perception as well as under- and overperception of asthma symptoms and can guide the development of affect-related interventions to improve perceptual accuracy, asthma control and quality of life in asthma patients.