Negative symptoms represent a core aspect of schizophrenia, significantly impacting patients’ lives and posing challenges to healthcare systems globally. Despite their acknowledged importance, these symptoms have historically been neglected and understudied, also due to classification systems and diagnostic criteria that marginalized their importance. However, recent advancements have brought these symptoms to the forefront of research and clinical practice, recognizing their profound influence on functional outcome and treatment response. Starting with an exploration of the historical evolution of the negative symptoms concept, this chapter explores the current conceptualization, definition, and longitudinal trajectory of negative symptoms in schizophrenia, describing their complexity and clinical relevance. It offers an updated perspective on these symptoms, underscoring their heterogeneity and the importance of incorporating current conceptualizations on negative symptoms into clinical approaches and research investigations.