This chapter evaluates whether insomnia patients are sleepier than healthy controls without insomnia. In order to assess whether insomnia patients suffer from sleepiness, the authors assessed the extent to which treatments for insomnia improved some measure related to daytime sleepiness. The current literature suggests that insomnia is frequently associated with greater self-reported daytime sleepiness than is seen in healthy individuals without sleep complaints. The multicomponent cognitive-behavioral therapy had a significant advantage over the control therapy in decreasing number of naps per week. Some have hypothesized that this mismatch reflects a hyperarousal state in insomnia that prevents the daytime sleepiness that they experience from becoming manifest in objective daytime sleepiness. The findings of treatment studies provide preliminary evidence that insomnia patients have some degree of daytime sleepiness that can be improved with treatment.