This essay explores the critical role of business ethics and sustainability in organizational behavior, highlighting the prevalence of unethical practices in today's competitive business environment. It defines unethical behavior and discusses its causes, such as perceived unfair treatment, misguided loyalty, and condoned misconduct, emphasizing the negative impact on society and individual well-being. The essay presents a case study of Zara, a company criticized for unethical treatment of employees, including poor working conditions, long hours, and unauthorized outsourcing. The analysis identifies competition and profit maximization as primary drivers of Zara's unethical practices, alongside the absence of a strong ethical code. The essay concludes that ethical behavior is essential for sustainable business growth and societal well-being, contrasting it with the detrimental effects of unethical actions exemplified by Zara's practices.