“Restricted or fixated interests that are abnormal in intensity or focus” can mean different things to different people. In this chapter, the authors note that “restricted” does not necessarily imply that the interest eclipses all other considerations in a person’s life. Additionally, “intense” can manifest in different ways, including frequency of thought or intensity of emotions. Intensity and atypicality of interests must also be considered in the context of the person’s developmental level and culture; for example, an interest that is atypical in one culture may be typical in another, and an interest that is typical for one age may be atypical for another. The interests of autistic women and girls are more likely to be intense than atypical and often center on people, animals, reading, and pop culture, rather than objects or data. Daydreaming is an intense interest that can be positive or can become problematic when a person becomes so immersed in thinking about a fantasy world that they fail to notice their environment or meet basic expectations for work or school (referred to as maladaptive daydreaming). Because many autistic people have learned to hide their intense or atypical interests from others, it is important to ask them about their experiences.