IMPORTANCE: In the absence of a vaccine and therapeutic agent, personal hygiene and physical distancing are essential measures to contain the coronavirus disease 2019 pandemic. OBJECTIVE: To determine whether a social media campaign, targeted at the gaps in behavior on personal hygiene and physical distancing and distributed nationwide via digital news media, may be an effective method to improve behavior and help to inhibit person-to-person transmission of severe acute respiratory syndrome coronavirus 2. DESIGN, SETTING, AND PARTICIPANTS: This survey study was designed to uncover self-reported gaps in behavior regarding personal hygiene and physical distancing in the Netherlands. A diagnostic survey was distributed by a large national newspaper (De Telegraaf) and a popular social influencer (Govert Sweep) on March 17, 2020, and was completed by 16 072 participants. Analysis of these outcomes showed that coughing and sneezing in the elbow was done well, but that handwashing, face touching, and physical distancing showed serious gaps compared with advised behavior. This diagnostic information was used to design infographics and a video targeted at repairing these gaps in behavior. The video and infographics were distributed on a national level on March 21, 2020, followed by a postcampaign survey to measure the results on March 24, 2020. Data analysis was performed from March to April 2020. EXPOSURE: Exposed participants were those who viewed the infographics and/or video. MAIN OUTCOMES AND MEASURES: Improvement on the extent of handwashing in all areas, handwashing duration of 20 seconds or longer, awareness on face touching, and physical distancing were measured according to responses on the postcampaign survey. RESULTS: A total of 17 189 participants (mean [SD] age, 47.61 [13.57] years; 9100 women [52.9%]) responded to the postcampaign survey. The news article in De Telegraaf was read more than 2 million times, and the influencer video was watched more than 80 000 times. Cross-sectional analysis of the postcampaign survey using logistic regression correcting for age, gender, and educational level showed that exposure to the video plus infographics (827 participants) (adjusted odds ratio [OR], 2.14; 95% CI, 1.83-2.50; P < .001) and to the infographics alone (11 348 participants) (adjusted OR, 1.31; 95% CI, 1.22-1.40; P < .001) were positively associated with washing hands in all areas compared with the unexposed group (4751 participants). In addition, exposure to the video plus infographics (adjusted OR, 1.86; 95% CI, 1.59-2.16; P < .001) and to the infographics alone (adjusted OR, 1.27; 95% CI, 1.19-1.36; P < .001) were positively associated with washing hands long enough compared with the unexposed group. Exposure to the video alone was not associated with improved handwashing. Compared with the unexposed group, exposure to the infographics alone and video plus infographics were associated with improvements in physical distancing when the participant had COVID-19 syptoms (infographics alone, adjusted OR, 1.10; 95% CI, 1.03-1.17; P = .006; video plus infographics, adjusted OR, 0.79; 95% CI, 0.69-0.91; P = .001) and face touching (infographics alone, adjusted OR, 1.29; 95% CI, 1.22-1.38; P < .001; infographics and video, adjusted OR, 1.49, 95% CI, 1.30-1.71; P < .001). CONCLUSIONS AND RELEVANCE: These findings suggest that a targeted behavioral change campaign, promoted by a news platform and social media, was associated with self-reported improvement in personal hygiene with the aim to prevent person-to-person transmission of severe acute respiratory syndrome coronavirus 2. This method of evidence-based campaigning may be an effective way to improve critical public health issues, such as the coronavirus disease 2019 pandemic.