<p>Sleepiness is one of the possible diurnal consequences of insomnia. However, this construct demands appropriate measures to cover its different dimensions. Previous studies have shown that daytime sleepiness perception is likely the most relevant sleepiness facet of insomnia. The purpose of the current study was to enhance the psychometric properties of the Daytime Sleepiness Perception Scale (DSPS-4), which is a brief self-report instrument consisting of four items aimed at evaluating daytime sleepiness perception, particularly in insomnia. A sample composed of 537 Portuguese higher education students (75% women) across the country completed a set of online questionnaires, including the DSPS-4. All items comprising the scale differentiated the “insomnia” group from the “noninsomnia” group. Confirmatory factor analysis supported a single factor solution, although item four loaded significantly lower than the remaining items did. Item response theory indicated that this item did not provide significant information across the latent trait continuum. Finally, network analysis revealed that item four was the only item associated with sleepiness propensity as measured by the Epworth Sleepiness Scale. This item seems to be more related to sleepiness propensity and, to a lesser extent, to sleepiness perception. The DSPS-4, which is currently labeled the DSPS-R, remains an adequate and promising tool for assessing daytime sleepiness perception in insomnia patients. Since one of its items is proposed to be deleted, the instrument now consists of only three items.</p>