This paper provides a comprehensive review of the applications, barriers, and future directions of artificial intelligence (AI) in smart cities. It analyzes literature published between 2021 and 2024, focusing on six key areas: smart governance, smart economy, smart mobility, smart environment, smart living, and smart people. The study identifies AI solutions, challenges, and opportunities in each area, offering insights into how AI can enhance urban life while addressing ethical, technical, and social concerns. In smart governance, AI is used to improve public administration, enhance transparency, and facilitate citizen engagement. AI-driven chatbots, multi-agent systems, and data analytics are employed to streamline administrative processes and improve decision-making. However, challenges such as data privacy, ethical concerns, and the complexity of integrating AI into existing systems remain significant barriers. Future directions include the development of more transparent and accountable AI systems, as well as the integration of AI with cybersecurity and predictive policing. In the smart economy, AI is transforming business operations, financial systems, and economic development. AI-powered platforms support entrepreneurship, optimize supply chains, and enhance productivity. However, challenges such as data security, ethical considerations, and the shortage of skilled professionals hinder AI adoption. Future directions include the development of smart financial systems, the integration of AI with blockchain and digital currencies, and the promotion of financial inclusion. In smart mobility, AI is used to optimize traffic management, reduce congestion, and improve transportation efficiency. AI-powered systems analyze real-time data to predict traffic patterns and adjust signal timings. Autonomous vehicles and shared mobility systems also benefit from AI technologies. Challenges include ensuring data privacy, addressing ethical concerns, and ensuring the reliability of AI systems. Future directions involve the development of more intelligent and interconnected transportation networks. The paper also highlights the importance of ethical considerations, data privacy, and public trust in the successful implementation of AI in smart cities. It emphasizes the need for transparent, accountable, and inclusive AI solutions that align with societal values and ensure equitable access to technology. The study concludes that while AI offers significant potential to enhance urban life, its implementation requires careful planning, ethical guidelines, and collaboration among policymakers, technologists, and citizens.This paper provides a comprehensive review of the applications, barriers, and future directions of artificial intelligence (AI) in smart cities. It analyzes literature published between 2021 and 2024, focusing on six key areas: smart governance, smart economy, smart mobility, smart environment, smart living, and smart people. The study identifies AI solutions, challenges, and opportunities in each area, offering insights into how AI can enhance urban life while addressing ethical, technical, and social concerns. In smart governance, AI is used to improve public administration, enhance transparency, and facilitate citizen engagement. AI-driven chatbots, multi-agent systems, and data analytics are employed to streamline administrative processes and improve decision-making. However, challenges such as data privacy, ethical concerns, and the complexity of integrating AI into existing systems remain significant barriers. Future directions include the development of more transparent and accountable AI systems, as well as the integration of AI with cybersecurity and predictive policing. In the smart economy, AI is transforming business operations, financial systems, and economic development. AI-powered platforms support entrepreneurship, optimize supply chains, and enhance productivity. However, challenges such as data security, ethical considerations, and the shortage of skilled professionals hinder AI adoption. Future directions include the development of smart financial systems, the integration of AI with blockchain and digital currencies, and the promotion of financial inclusion. In smart mobility, AI is used to optimize traffic management, reduce congestion, and improve transportation efficiency. AI-powered systems analyze real-time data to predict traffic patterns and adjust signal timings. Autonomous vehicles and shared mobility systems also benefit from AI technologies. Challenges include ensuring data privacy, addressing ethical concerns, and ensuring the reliability of AI systems. Future directions involve the development of more intelligent and interconnected transportation networks. The paper also highlights the importance of ethical considerations, data privacy, and public trust in the successful implementation of AI in smart cities. It emphasizes the need for transparent, accountable, and inclusive AI solutions that align with societal values and ensure equitable access to technology. The study concludes that while AI offers significant potential to enhance urban life, its implementation requires careful planning, ethical guidelines, and collaboration among policymakers, technologists, and citizens.