This study, through a comparative analysis of two cases adjudicated in separate forums, both involving contractual relationships governed by Iranian law, examines the reciprocal influence between the governing law and the forum. The first case study reveals that despite the Iranian legal system's closer affiliation with civil law traditions, which typically emphasise discerning the parties' intentions in contract interpretation, the English court's understanding of Iranian principles of construction aligned more closely with the literal and objective approach characteristic of common law systems. In the second case, the absence of specific provisions in Iranian law regarding certain interpretative rules, such as the principle of good faith or the contra proferentem rule, prompted the arbitral tribunal to partially set aside Iranian law as the governing law and address certain aspects of the dispute based on Swiss law (the seat of arbitration). This research demonstrates that even fundamental principles of the governing law are not inviolable in international adjudications. Foreign courts or arbitral tribunals may select rules of construction based on their own legal traditions or intellectual frameworks, even when such approaches diverge from those of the governing law. In the context of Iranian principles of construction, the lack of explicit provisions on interpretative rules has aggravated this issue, resulting in misinterpretations of the governing law in some cases. This phenomenon illuminates the intricate interplay between governing law and forum in international dispute resolution, illustrating how the legal tradition of the forum can profoundly shape the application and interpretation of the governing law.