Purpose: Injured workers can experience adverse effects from work injury and claims processes.Workers may be treated unfairly by employers, compensation boards, and return-to-work coordinators; however,how workers respond to these challenges is unknown. This article describes how injured precarious workersresponded behaviourally and emotionally to procedural unfairness in work injury and claims processes, and whatworkers did next. Methods: Interviews were conducted with thirty-six precariously employedinjured workers recruited in Ontario through social media, email, cold calling, word-of-mouth, and the “snowball”method. Thematic code summaries were analyzed to identify how precarious workers responded to procedural unfairness. Results: Workers went through all or most of these five stages (not always linearly)when faced with procedural unfairness: (1) passive, (2) fought back, (3) quit pursuit of claim, (4) quit job, and (5)won or got further in fight. Feeling confused, angry, frustrated, unsupported, disappointed, determined, optimistic,and wary were common emotions. Conclusions: Identifying unfairness and its emotional,behavioral, and material effects on workers is important to understand implications for compensation systems.Understanding and recognizing unfairness can equip employers, legal representatives, compensation boards, andphysicians, to address and prevent it, and provide worker resources. Policy changes can ensure accountability andconsequences to unfairness initiators. Supplementary Information The online version contains supplementary material available at 10.1007/s10926-022-10058-3.