The transport sector is a major contributor to global greenhouse gas emissions, making its decarbonization critical for climate change mitigation efforts. The Marginal Abatement Cost (MAC) curve is a vital tool that evaluates the cost-effectiveness of mitigation measures by comparing their emission reduction potential against their implementation costs. This paper conducts a literature review to analyze the application of the MAC curve in the transport sector, identifying common mitigation measures, comparing abatement costs, and assessing the tool’s role in shaping decarbonization policies. The findings reveal a predominance of technology-focused, bottom-up methodologies, with a significant research gap in the freight sector, which is largely overlooked compared with passenger transport. The results show that the abatement costs for similar measures vary considerably across geographical contexts, influenced by local factors such as fuel prices and gross domestic product (GDP). The analysis suggests that combining technological solutions with behavioral and structural changes creates synergistic effects, yielding greater benefits than isolated actions. The strong alignment observed between measures analyzed in the literature and subsequent national climate policies confirms the MAC curve’s strategic importance as an evidence-based instrument for policymakers to construct economically rational decarbonization pathways.