Our consumer-driven culture has negative impacts for individuals who are vulnerable to clinical hoarding and compulsive shopping. Because of this, there is an ever-present need to have standardized tools to assess why we acquire and save things we might not need. In this article, we present the development of the Acquiring Motives Questionnaire (AMQ) and Saving Motives Questionnaire (SMQ), which were written based on a thorough literature review and consultation with 22 experts in the field. After piloting with two large nonclinical samples, we administered the measures to another large nonclinical sample (N = 535; Mage = 24.4, 74.2% female, 54.6% White) and then a community sample of individuals with hoarding disorder and/or compulsive buying–shopping disorder and controls without any mental health diagnoses (N = 159; Mage = 42.54, 85.5% female, 59.7% White). Confirmatory factor analyses supported a 14-factor model for the AMQ and a 14-factor model for the SMQ. All subscales demonstrated good internal consistency (ω = 0.81–0.96), 2-week test–retest reliability (intraclass correlation coefficient = 0.67–0.83), and convergent, divergent, and criterion validity. The measures also distinguished between controls and individuals with hoarding and/or compulsive buying diagnoses. Findings highlight that acquiring and saving behaviors are both motivated by the pursuit of positive emotions and the avoidance of negative emotions, which is consistent with our theoretical understanding of these clinical issues. Based on our findings, we make suggestions for psychological interventions. Public Significance Statement: Current levels of overconsumption, particularly in capitalist societies, are environmentally unsustainable and have negative consequences for individuals vulnerable to compulsive shopping and hoarding. This is because many consumers buy too many nonessential products, often due to psychological reasons rather than actual needs. This article developed a new measure for the psychological motivations that drive the excessive acquisition and saving of possessions. [ABSTRACT FROM AUTHOR]