This systematic literature review explores the evolution of research design in the social sciences, focusing on the methodological developments, challenges, and innovations that have shaped the field over time. The review traces the historical trajectory of research methods, starting from the dominance of positivist paradigms and the gradual incorporation of qualitative methodologies. The integration of mixed-methods approaches, which combine quantitative and qualitative techniques, has emerged as a significant milestone, allowing researchers to address multifaceted research questions with greater depth and rigor. Technological advancements, including the rise of digital tools such as online surveys, social media analytics, and machine learning, have further transformed research practices, enabling large-scale data collection and analysis. However, these developments also introduce new ethical dilemmas, particularly concerning data privacy and representation, which require robust frameworks to guide researchers. Additionally, the review highlights the increasing emphasis on ethical considerations, particularly participatory and inclusive research methodologies, which prioritize marginalized voices and emphasize reflexivity. Interdisciplinary collaborations have been crucial in driving methodological innovation, as social scientists collaborate with researchers from other fields to address complex global issues such as climate change, public health, and social inequality. Finally, the review discusses the pedagogical implications of these developments, emphasizing the importance of fostering critical thinking, methodological literacy, and ethical sensitivity among students and researchers. This review provides a comprehensive overview of the evolving landscape of research design in social sciences, offering insights into future directions for methodological advancement.