Restrictive and Repetitive Behaviors and Interests represent a core feature of autism since the earliest conceptualization of the condition. Related behaviors, such as hoarding and self-injurious behaviors, are under-researched in adulthood, resulting in limited knowledge about their various manifestation through the life span. This study expands our understanding of hoarding and self-injurious behaviors through subjective experiences shared by autistic adults. Ten adults with an autism diagnosis (aged 18-55 years, five females) participated in semi-structured, in-depth interviews. Thematic analysis identified a cluster of behaviors related to hoarding and self-injurious behaviors. Further analysis sub-categorized each theme according to the underlying purpose of the behavior. Hoarding behaviors were motivated by (1) a need for emotional aids, (2) disposing difficulties, and (3) collecting items related to special interests. Reasons for engaging in self-injurious behaviors were (1) an urge for sensory stimulation and (2) emotional regulation purposes. Discussion focuses on the underlying motives of the participants for engaging in these behaviors, in respect to current research knowledge. Relations to the general construct of Restrictive and Repetitive Behaviors and Interests are discussed along with implications for research and practice.