Both leaf and stomatal movements are essential to plant physiology, enabling plants to enhance their gas exchange, water conservation, and photosynthetic efficiency by environmental factors. The coordinated motions are influenced by the intricate interplay between internal circadian rhythms and external stimuli, including light, temperature, and humidity. Based on the circadian clock, light perception, and hormonal signals, stomatal opening and closing adhere to predictable diurnal patterns that control transpiration and CO₂ absorption. Leaf movements, which include sleep movements in certain species, are also controlled by daily cycles and have crucial functions in safeguarding against oxidation and optimizing the process of photosynthesis. This chapter delves into the fundamental processes responsible for these rhythmic movements, analytically investigating the involvement of photoreceptors, ion channels, fluctuations in turgor pressure, and hormonal pathways. Furthermore, it examines the ecological and agricultural importance of these processes, specifically investigating the impact of environmental factors on the coordination of leaf and stomatal rhythms with external periodicity.