This chapter examines disorganized thinking and motoric behaviors as multidimensional, transdiagnostic phenomena central to serious mental illness (SMI), particularly schizophrenia spectrum disorders. Etiologically, these behaviors stem from disrupted thought processes, impaired metacognition, and affective antecedents such as shame, alienation, and interpersonal tension. Epidemiological data highlights their prevalence across psychiatric and neurological conditions, with disorganized speech marked by derailment, tangentiality, incoherence, and neologisms that impair communication and social functioning. Motoric disorganization, including catatonia and purposeless agitation, further compromises adaptive behavior. Behavioral strategies emphasize dimensional assessment using validated tools such as the Thought, Language, and Communication (TLC) scale and the Bern Psychopathology Scale-Revised (BPS-R), which capture severity, frequency, and contextual triggers. This chapter outlines behaviorally anchored interventions targeting antecedent emotional distress, operationalization of observable behaviors, prompting and reinforcing adaptive behaviors, and enhancing awareness of disorganization triggers to support recovery and improve functional outcomes.