Environmental issues have become of prime importance nowadays so that they are a recurrent subject at the table of the world's most powerful committees. Hence, the relationship between environmental regulation, eco-innovation and firms' competitiveness has always been equivocal. All the concerned groups of interest claim to have the right argument without a convincing proof. The present book will shed some light on one of the most controversial hypothesis in the last couple of decades: the Porter Hypothesis. The book is divided in two main parts: First, a review of the existing literature around the porter hypothesis, including some skeptical opinions. The second part consists of an empirical model to test the Porter hypothesis based on a panel of nearly 30,000 German companies. This book will therefore be suitable for students and researchers who want to have a synthesized idea about the subject with an econometric analysis to accept or refute the six hypotheses stipulated in this work. The book will also be a useful tool to all decision makers whether firm's managers or civil servants who want to have an up to date idea of the debate concerning regulation and competitiveness.