University students commonly experience sleep problems which have implications for daily functioning and academic achievement. For this reason, research is needed to identify modifiable individual difference variables that may contribute to better sleep in this population. Temperament and sleep hygiene may be two such factors. As part of a larger study, 167 university students (61.7% female) completed online questionnaires that inquired about temperament (the Adult Temperament Questionnaire; ATQ), sleep hygiene behavior (the Sleep Hygiene Index; SHI), global sleep quality (the Pittsburgh Sleep Quality Index; PSQI), and insomnia severity (the Insomnia Severity Index; ISI). Correlations amongst the included measures were in the predicted direction: effortful control was negatively associated with the SHI composite, PSQI global scores, and ISI scores; extraversion was negatively related to PSQI global scores; and negative affect was positively associated with the SHI composite and ISI scores. In addition, the SHI composite mediated the association between effortful control and the PSQI global scores as well as the association between negative affect and PSQI global scores; similar patterns of mediation were found when considering ISI scores, although the direct effects differed. That is, negative affect was directly associated with ISI scores but not PSQI global scores. These findings suggest that interventions designed enhance effortful control, reduce negative affect, and improve sleep hygiene may contribute to better global sleep quality and decrease insomnia in university students.