Eco-labels, in the context of energy tariffs, are intended to ensure consumers a sustainable electricity generation. The main objective of this study is to investigate if available eco-labels have an influence on consumers’ choices in electricity tariffs. The study also examines the relative importance of other common attributes of electricity tariffs, namely the type of supplier, the electricity mix, the share of regional generation, and the price. Data was gathered using a two-part stated preference online survey in Germany, with 165 participants in total. In the first part, a Choice-Based Conjoint (CBC) survey was conducted. In the second part of the survey, participants were asked to complete choice tasks following the Maximum Difference Scaling (MaxDiff) methodology. Results using Hierarchical Bayesian (HB) analysis show substantial differences in the two survey parts. While sustainability is most important in the MaxDiff part, CBC results suggest that the price is the decisive factor when choosing an electricity tariff. Furthermore, eco-labels seem to have a big influence on the consumers’ choice behavior. On the contrary, analysis of the general awareness levels reveals that the certification criteria of the eco-labels are unknown to the majority of consumers, often even the labels themselves.