Online marketing to humans in their childhood, adolescent and early adulthood is an increasingly important research topic because it can on a larger scale than previously possible with traditional marketing lead to undesirable outcomes (e.g., obesity) and target more ethical grey zones between questionable, unfair and deceptive marketing to achieve its goals (Buijzen & Valkenburg, 2005; De Pauw et al., 2019). In particular, social media influencer content and embedded marketing might have a large influence on young consumers (Folkvord et al., 2019).The largest recent research trend and solution to address the problems related to online young consumer marketing was the establishment of online marketing disclosure policies (De Veirman et al., 2019; FTC, 2017; Gürkaynak et al., 2018; Riefa & Clausen, 2019). Disclosures have their merits, but also shortcomings. In particular, increased process fairness (i.e., awareness of the selling intent) appears not to be enough to diminish undesirable outcomes because young consumers also need the knowledge and the skills to counter the undesirable effects resulting from marketing exposures (De Pauw et al., 2019; Isaac & Grayson, 2019; Jung & Heo, 2019; Youn & Shin, 2019). In intervention research targeting the increase of knowledge and skills of children, the largest yet comparatively small trend are school-based interventions (De Jans et al., 2019; Nelson, 2016; O’Rourke et al., 2019; Truman & Elliott, 2019). However, school-based interventions have a few vital shortcomings. First, school-based marketing literacy interventions are costly to scale. Second, they create further competition for scare school-based financial, human and attention resources. Lastly, they might not be frequent or context-specific enough to produce a lasting change in marketing-related knowledge and skills. In contrast, parent-targeted interventions that increase the parental intentions to engage in behaviors that increase marketing-related knowledge and the skills of children do not have these shortcomings and, as a result, can be considerably more important for researchers and policymakers (De Pauw et al., 2019; Isaac & Grayson, 2019; Jung & Heo, 2019; Youn & Shin, 2019). Compared to school-based interventions, parents have more opportunities and time to influence the media diet directly and educate them with higher frequency and higher context-specificity by daily discussing the marketing their children actually engage with (Chen & Shi, 2019; Lin et al., 2019; Nelson et al., 2017). Consequently, the thesis purpose was to advance the knowledge of interventions that target parental intentions to engage in marketing-literacy-relevant behaviors. To this end, the study combined a conceptual and theoretical framework based on the theory of planned behavior (TPB) and broader intervention science concepts, in particular behavioral change techniques (BCTs) and mechanisms of actions (MoA), and an advanced experimental design. More specifically, 21 theory-informed hypotheses were tested in a randomized controlled online experiment composed of six interventions and one control condition with a sample of 196 (pre-intervention and immediately post-intervention) and 166 participants (one-month post-intervention).Numerous contributions are made. First, relatively brief (35 minutes) TBP-based online interventions can have a significant effect on parental intentions to engage in the discussion of influencer marketing and on self-reported one-month post-intervention behaviors. Second, the combined framework was highly valuable to inform an intervention design that produces effects of practical and theoretical importance. Third, the parsimonious TPB-based model (i.e., consistent of attitudes, subjective norms, perceived behavioral control and intentions) is also appropriate for the context of parental mediation of influencer marketing because the three-based constructs could significantly explain the majority of parental intentions (74%), and parental intentions alone significantly predicted a moderate amount variance in the future behaviors (39%). Fourth, parental attitudes were the base-construct most susceptible to change and considerably predicted intentions. Therefore, research efforts should focus on the study of parental attitudes and practical efforts should focus on targeting parental attitudes until marketing and influencer marketing become mainstream topics in the parental discourse. Lastly, despite the high intentions in the attitude only condition, the condition had no significant impact on future behaviors. Even though the attitude and three-construct condition shared an identical intention level, the three-construct intervention had a marginally non-significant (.06) effect on future behaviors. The four-construct had a significant effect on future behaviors. As a result, time spent (10 minutes vs. 33 and 35 minutes) and associated elaboration might be an important moderator of future behavior.