Children today are surrounded by and immersed in media such that it pervades almost every aspect of their daily lives. The potential effects of media content are of particular interest for elementary school children, who are old enough to use media alone, but too young to fully understand everything they see. One way of enhancing the benefits and reducing the harm of media is through parental mediation. A good deal of research has been conducted on parental mediation, especially regarding children's television use; however, existing measures of parental mediation are in need of an updated evaluation. In addition, very little research has examined how parents might be mediating newer digital media. The present dissertation study sought to fill in these gaps by investigating the validity of the most significant measure of television mediation (Valkenburg et al., 1999) and exploring the ways in which parents are mediating the internet, smartphones, and tablets. Two online surveys were conducted with parents of children between the ages of 6 and 12 to test questions related to the mediation of television (N = 301) and digital media (N = 299). Based on responses to this first set of surveys, a larger survey was developed and administered online to 701 parents. Parents responded to closed-ended scales of mediation and context-specific scenarios for television and digital media, as well as assessments of children's aggression, prosocial behavior, academic achievement, and multiple intelligences. Television mediation scenarios revealed that there are weaknesses in the construct validity of Valkenburg's television mediation scale, but the scenarios added little to the predictive validity over and above that of the Valkenburg scale. For digital media, the scale demonstrated weak construct and predictive validity. The digital media scenarios suggest that these results may be due to parents inconsistent and/or lack of mediation. The findings establish the significance of parental mediation, but also identify limitations in assessment and provide action steps to help move this research forward. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]