Sleep wake cycle is synchronized with the circadian clock fluctuations in Suprachiasmatic nucleus which are entrained with other diurnal rhythms in our body like feeding and fasting timings, temperature regulatory mechanisms and various hormonal level fluctuations. Due to change in our culture or lifestyle which lead to increased number of evening and night time work and leisure activities, less hours are available for sleep. Sleep deprivation alters both metabolism and endocrine function, including glucose tolerance and the hormone that controls hunger. This review looked at potential connections between sleep and factors that contribute to the pathogenesis of obesity. Studies showed that suggested that sleep restriction has metabolic effects that predispose to weight gain. Sleep loss found to be associated with increase in appetite via increasing Ghrelin and endocannabinoids whereas decreasing Leptin hormone. Because of sleep disruptions, time spent awake gave more opportunity for night time snacking and daytime sleepiness which might lead to decreased activity level. Hence overall positive balance in spite of increased energy expenditure leading to weight gain. Increase in sleep debt subsequently leads to fatigue and daytime sleepiness making prone to sedentary lifestyle and can predispose to obesity. Sleep disorders were linked directly with obesity severity in literature. The sleep fragmentation in sleep disorders like OSA might lead to excessive daytime sleepiness, lack of physical activity and increasing food intake by influencing food choices and hence, to obesity. OSA patients with CPAP therapy (continuous positive airway pressure) showed improvement not only in OSA severity but weight loss also. Therefore, scheduling sleep might improve the obesity and further consequences of obesity like cardiovascular disorders or metabolic syndrome etc. Hence, sleep should be considered equally important as nutrition and exercise.