The increasing volume of litigation and the limited resources of the judiciary have raised a central question for contemporary procedural systems: how to balance the ideal of truth-finding in each case with the need for procedural efficiency. The principle of procedural proportionality has emerged as a strategic response to this challenge, requiring judicial resources -temporal, financial, and human- to be allocated in accordance with the nature, value, complexity, and circumstances of each dispute. Using a descriptive-analytical method and library-based sources, this study comparatively examines the status of proportionality in the procedural systems of the United States, England, Canada, France, and Iran. It also analyzes its functions in five key areas: procedural economy, procedural time, procedural formalities and judicial organization, provisional measures and procedural sanctions, and the law of evidence. The findings show that, while proportionality has been expressly recognized as a guiding principle in some common-law systems, its presence in civil-law traditions is mainly implicit. In Iranian law, although not expressly established as an independent procedural principle, its logic can be traced in jurisprudential, legislative, interpretive, and judicial contexts. The study concludes that Iranian law is at an intermediate stage, requiring legislative clarification and doctrinal development to consolidate procedural proportionality.