<b><i>Background:</i></b> Tobacco product warning labels are a key health communication medium with plain packaging noted as the next step in the evolution of tobacco packaging. We assessed the self-reported impact of text versus pictorial health warnings and the determinants of support for plain packaging of tobacco products in the European Union (EU). <b><i>Methods:</i></b> The Special Eurobarometer 385 survey was analyzed for 26,566 adults from 27 EU countries in 2012. The self-reported impact of warning labels (text or pictorial) and determinants of EU-wide support for plain packaging were assessed using multivariate logistic regression. <b><i>Results:</i></b> Current smokers in countries where cigarette pictorial warnings were implemented had higher odds of reporting that health warning labels had any effect on their smoking behavior (making a quit attempt or reducing number of cigarettes smoked per day) compared to respondents in countries with text-only warning labels (adjusted odds ratio, aOR = 1.31; 95% confidence interval, 95% CI: 1.10-1.56). Population support for plain packaging of tobacco packs was higher in countries where cigarette pictorial warnings already existed (aOR = 1.17; 95% CI: 1.07-1.28). <b><i>Conclusions:</i></b> These findings indicate that the implementation of pictorial warnings at an EU level may have a positive behavioral impact among smokers and pave the way for population support for plain packaging in the EU.