Recent research has demonstrated that parents’ beliefs about their children's minds constitute an important environmental factor affecting children's development. One difficulty with this area of investigation is that beliefs are often implicit, unconscious, and not always accessible through direct questioning. This study addresses this difficulty by developing a conceptual framework for determining mothers’ beliefs from the ways that they described their 12- to 24-month-old infants. Grounded theory techniques were used to analyze the language used by 25 Australian mothers during semi-structured, open-ended interviews. Their descriptions of their infants’ behavior and personal attributes were analyzed according to the mind-related constructs that they contained and the various ways in which these descriptions communicated their beliefs. A model was then developed to represent the psychological and inferential complexity associated with particular infant descriptions. The use of mothers’ own words to derive and illustrate their beliefs adds authenticity and ecological validity to the model, and provides a means of situating children's acquisition of particular ways of thinking within the psychological context of the family.