The principle of honesty, as one of the fundamental pillars of fair trial, requires litigants to act in good faith in all stages of the litigation process and to refrain from adversarial actions and abuse of judicial facilities. Despite the important position of this principle in advanced legal systems, Iranian law has not independently and coherently addressed the guarantees for its violation. The present article aims to analyze the guarantees for violating the principle of honesty in Iranian civil procedure and to identify the challenges ahead. This research, using a descriptive-analytical method, examines the concept and examples of violation of the principle of honesty (such as filing a frivolous lawsuit, concealing the truth, and intentionally delaying the proceedings), and studies the relevant legal bases in the Civil Procedure Code and judicial practice. The research findings show that although in Iranian law, guarantees such as conviction for litigation damages, dismissal of the lawsuit, and sometimes disciplinary guarantees can be applied, the existing legal system faces fundamental challenges, including the lack of a precise legal definition of concepts such as "frivolous lawsuit" and "bad faith," the dispersion of regulations, and cautious judicial practice. Also, the powers of the courts to apply guarantees commensurate with the severity of the violation, especially final guarantees such as issuing a dismissal order, face serious ambiguities.