Eco-certification has become an increasingly popular market-based tool in the endeavor to reduce negative environmental impacts from fisheries and aquaculture. In this study, we aimed at investigating which psychological consumer characteristics influence demand for eco-labeled seafood by correlating consumers' stated purchasing of eco-labeled seafood to nine variables: environmental knowledge regarding seafood production, familiarity with eco-labels, subjective knowledge, pro-environmental self-identification, sense of personal responsibility, concern for negative environmental impacts from seafood production, perceived consumer effectiveness, gender and education. Questionnaires were distributed to consumers in Stockholm, Sweden, and the data were tested with multiple regression analysis using linear modeling and model averaging (n = 371). Two variables were the best predictors of stated purchasing of eco-labeled seafood: (i) recognition and understanding of eco-labels for seafood (Marine Stewardship Council, Fish for Life, Aquaculture Stewardship Council and KRAV); and (ii) concern for negative environmental impacts associated with seafood production. Meanwhile, consumer environmental knowledge was a weaker predictor. Results from this study suggest that strengthening the emotional component of consumer decision-making and improving the level of consumer familiarity with seafood eco-labels could stimulate more pro-environmental seafood consumption.