Long-chain polyunsaturated fatty acids (LCPUFAs) are semi-essential fatty acids widely studied in adult subjects for their healthy-heart effects, especially on secondary prevention in patients who already experienced a cardiac event. LCPUFAs consumption is safe, without adverse effects, and they are usually well-tolerated; they can be taken either in foods or as nutritional supplements. LCPUFAs' positive effect on global health has been worldwide recognized also for pediatric patients. In childhood and adolescence, research has mainly focused on LCPUFAs' effects on neurodevelopment, brain and visual functions and on maternal-fetal medicine, yet their cardiovascular effects in childhood are still understudied. Atherosclerosis is a multifactorial process that starts even before birth and progresses throughout life; thus, cardiovascular prevention is advisable and effective from the very first years of life. Nutritional and lifestyle interventions are the main factors that can interfere with atherosclerosis in childhood, and the consumption of specific nutrients, such as LCPUFAs, can enhance positive nutritional effects. The aim of our narrative review is to analyze the effect of LCPUFAs on cardiovascular risk factors and on cardiovascular risk prevention in developmental age, focusing on specific conditions such as weight excess and dyslipidemia.