Parlor palms are popular indoor palm trees that are low-maintenance and offer great benefits. However, when the leaves start turning yellow, it can be frustrating. There are ten common reasons for yellowing leaves on parlor palms: underwatering, overwatering, incorrect temperature and humidity levels, too much direct sunlight, lack of sunlight, wrong soil, lack of nutrients, over-fertilizing, transplant shock, and pests or diseases. Understanding and addressing these issues will help keep your parlor palm healthy and green.