The expansion of business activities through corporate groups has created a fundamental challenge for company law in reconciling the separate legal personality of companies with the economic reality of the group. In such structures, the parent company directs group policies through control and influence over its subsidiaries, while the principles of separate legal personality and limited liability formally remain intact. The principal question is how German law reconciles the economic integration of corporate groups with the legal autonomy of their member companies and to what extent this experience may inform Iranian law. Using a descriptive-analytical method and a comparative approach, and drawing on textual interpretation of statutory provisions, this study examines the fundamental concepts of German corporate group law, including dependence, control, unified management, contractual and de facto groups, and mechanisms for protecting creditors and minority shareholders, before assessing the position under Iranian law. The findings show that German law, through a dedicated regulatory framework for corporate groups, has established a coherent system governing parent-subsidiary relations and, through specific liability and protective mechanisms, achieved a relative balance between the economic efficiency of corporate concentration and the protection of stakeholders. By contrast, although Iranian law implicitly recognizes corporate groups through scattered provisions, it lacks a coherent framework governing the legal effects of control and unified management. Accordingly, adopting specific rules on corporate groups and parent-company liability is an important necessity for the development of Iranian company law.