T-cell lymphomas (TCLs) are a rare and heterogeneous group of non-Hodgkin lymphomas (NHL), often presenting at advanced stages and associated with poor prognosis. Subtypes include both indolent forms, such as cutaneous TCL (CTCL), and aggressive entities, including peripheral TCL (PTCL), anaplastic large cell lymphoma (ALCL), and angioimmunoblastic TCL (AITL). Diagnosis is challenging and relies on a combination of histopathology, immunophenotyping, and molecular studies. Treatment options remain limited, with CHOP-based chemotherapy and stem cell transplantation commonly used. However, new agents and combination therapies are emerging in this field. [18F]FDG PET/CT is considered a key tool for staging, biopsy guidance, and treatment response assessment due to the high FDG avidity of many of TCL subtypes. It offers superior sensitivity compared to conventional imaging and provides prognostic information through metabolic parameters such as SUVmax and metabolic tumor volume (MTV). While promising, the role of PET/CT in bone marrow assessment and interim response evaluation remains unclear and is under investigation. Further multicenter studies are needed to refine the general role of [18F]FDG PET/CT across TCL subtypes. Recently, artificial intelligence (AI) and radiomics have shown promising results when combined with clinical and laboratory data to enable risk stratification tools and enhance prognostication.