Search Engine Advertising: A Systematic Literature Review and Future Research Agenda

In the past two decades, search engine advertising (SEA) has evolved into a dominant form of digital marketing. Yet academic research in this domain remains fragmented across disciplines, highlighting the need for a comprehensive synthesis. Consequently, this study conducts a theory–context–method framework-based systematic literature review of 122 peer-reviewed articles published between 2021 and 2025, gathered from the Scopus database. The findings reveal a major theoretical deficit, with over 75% of studies lacking a formal framework. Contextually, SEA research clusters heavily within China and the US, leaving developing regions underrepresented and themes like privacy, ad design, and big data underexplored. Methodologically, while approaches range from econometric models to deep learning, quantitative designs heavily dominate (n = 87), leaving qualitative and mixed-methods research scarce. Additionally, this review proposes a future research agenda incorporating various theories (information foraging theory) and methods (goal programming) to advance scholarly and practical SEA understanding.