Objectives: Our study sought to determine the effects of valerian on sleep quality, depression, and state anxiety in hemodialysis (HD) patients. Methods: This randomized, double-blind, placebo-controlled, crossover clinical trial was conducted on 39 patients undergoing HD allocated into a valerian and placebo group. In the first phase of the study, group A (n = 19) received valerian and group B (n = 20) received a placebo one hour before sleep every night for a total of one month. Sleep quality, state anxiety, and depression were assessed in the patients at the beginning and end of the intervention using the Pittsburgh Sleep Quality Index, the Spielberger State-Trait Anxiety Inventory, and Beck Depression Inventory. In the second phase, the two groups' treatment regimen was swapped. After a one-month washout period, the same process was repeated on the crossover groups (i.e., group A received placebo and group B received valerian). Results: In the first phase, the mean sleep quality, depression, and state anxiety scores showed significant reductions in both groups, but the reduction was significantly higher in group A compared to group B (7.6 vs. 3.2, p < 0.001; 6.5 vs. 2.3, p = 0.013; 14.6 vs. 7.3, p = 0.003, respectively). In the second phase, the mean sleep disorder, depression, and state anxiety scores showed significant reductions in both groups, but the reduction was significantly lower in group A compared to group B (1.4 vs. 4.6, p < 0.001; 1.2 vs. 3.8, p = 0.002; 1.5 vs. 6.2, p < 0.001, respectively). Conclusions: Valerian significantly improved sleep quality, the symptoms of state anxiety, and depression in HD patients.