Radiation therapy in pediatric tumors has undergone a spectral change from conventional two-dimensional radiotherapy to intensity-modulated radiotherapy (IMRT) over last few decades. The complexity of pediatric diseases and its varied presentations have put the focus on the technological advancement to deal with site and disease specific challenges. The radiation therapy strategy has been driven by attempts to improve therapeutic index. This involves improving the disease control by exactly characterizing location and extent of the disease. The integration of technological advancements, such as computed tomography (CT) scans, magnetic resonance imaging (MRI), and positron emission tomography (PET) scans, has enabled radiation oncologists to define the structural and functional aspects of every tumor. The use of these modern imaging techniques and improved pathological classification of pediatric tumors helped oncologists to characterize these tumors according to their nature and predict prognosis. Furthermore, it has helped in predicting the recurrence pattern in various type of tumors. These factors, such as the nature of tumor, its extent, pattern of presentation, and recurrence, have dictated the radiotherapy techniques.