In the digital age, cities have become complex ecosystems of virtual interactions and data flows. This study aims to investigate the role of cyberspace in the transformation and redefinition of urban governance in the Tehran metropolis. The main research question is: what is the role of cyberspace in urban governance, and through what mechanisms has it led to the redefinition of urban governance in Tehran? The research method is descriptive-analytical with a qualitative approach (thematic analysis). In the first stage, the theoretical foundations of the network society and previous studies were utilized; then, in the survey stage, data were collected and analyzed through semi-structured interviews with 25 experts. The findings indicate that cyberspace acts as a catalyst in the governance process, leading to its improvement and facilitation. In terms of accountability, social networks reduce the distance between urban management and citizens, compelling institutions to react, yet the lack of binding systems renders accountability episodic. In terms of participation, applications such as "Man Shahrdāram" (I am the Mayor) have transformed citizens into active agents in urban decision-making. However, the optimal realization of governance faces structural challenges: lack of financial transparency, overlapping mandates of decision-making bodies (city council, municipality, Ministry of Interior), the predominance of a control-oriented approach (filtering) over smart regulation, and insufficient media literacy. Consequently, in Tehran, cyberspace has mostly become a tool for episodic demands rather than an institution for sustained participatory governance. Finally, the study proposes strategies to improve the current situation.