Enforcing and communicating sustainability is one of the biggest challenges for retailers in today’s business environment. Retailers are facing pressure from various stakeholders since the topic of sustainability is constantly moving up the agendas of companies, politics, and the media. Additionally, it is intensely discussed by a critical public. This dissertation consists of three related studies – one conceptual study and two research studies – that analyze sustainable behavior, reporting and communication in grocery retailing in Germany. In particular, sustainable behavior is compared across different retail formats. In the first study, the business model of grocery discounters and supermarkets is compared with respect to the impact on sustainability. The cost-leadership strategy applied by discounters is analyzed regarding its influence on strong and weak sustainability. The second article focuses on supermarkets, discounters and organic supermarkets. Based on the sustainability reports it is examined which information is disclosed and which legitimation strategies are applied if negative impacts have to be reported. The analysis revealed that, even within the same industry and country, a wide range with respect to quality levels of sustainability reporting exists. Furthermore, all retailers are reluctant about reporting negative aspects and frequently use similar legitimation strategies. The third article deals with communication of sustainability of both supermarkets and discounters comparing sustainability reporting and communication in the stores. It is shown that no clear difference between sustainability reporting of discounters and supermarkets was observable. However, supermarkets outperformed discounters with respect to in-store communication.:I. Sustainable Retailing – German Grocery Retailers and their Challenge of Communicating Sustainability 1 Introduction 1.1 Relevance and development of sustainability in academic research 1.2 Practically relevance 2 The entire Research Project 2.1 Related research, research questions and research objectives 2.2 Classification within related research streams 2.3 Overview publication status 3 Article Summary 3.1 Summary Article A: Discount Grocery Retailing: Cost-Leadership-Strategy versus Sustainability – Does it fit together? 3.2 Summary Article B: Sustainable Grocery Retailing: Myth or Reality? – A Content Analysis 3.3 Summary Article C: How do Supermarkets and Discounters communicate about Sustainability? – A comparative Analysis of Sustainability Reports and In-Store Communication 4 Dissertation Results, Contribution and Implications 5 Limitations and Future Research 6 Outlook 7 References II. Article A: Discount Grocery Retailing: Cost-Leadership-Strategy versus Sustainability – Does it fit together? 1 Introduction 2 Literature Review 2.1 Grocery discounters and traditional supermarkets 2.2 Cost-leadership-strategy and lean management within economic sustainability 2.3 The concept of “strong” and “weak” sustainability within sustainability research 3 Research Design 3.1 Research method 3.2 Analytical approach 4 Findings 4.1 Procurement and supply chain 4.2 Logistics and transportation 4.3 Store concepts and store design 4.4 Energy consumption and environment 5 Discussion and Analysis 5.1 “Strong sustainability” 5.2 “Weak sustainability” 5.3 Cost-leadership strategy contradicting sustainability 6 Conclusion, Limitations and Future Research 7 References III. Article B: Sustainable Grocery Retailing: Myth or Reality? – A Content Analysis 1 Introduction 2 Literature Review 3 Research Design 3.1 Research method and data collection 3.2 Analytical approach 4 Findings 4.1 General characteristics 4.2 Sustainability focus areas and coverage of GRI standards 4.3 Analysis of legitimating strategies 5 Discussion 5.1 Evaluation of sustainable reporting quality (RQ 1 and RQ 3) 5.2 Evaluation of reporting “negative aspects” for focus areas (RQ 2 and RQ3) 6 Conclusion 7 References IV. Article C: How do Supermarkets and Discounters communicate about Sustainability? A comparative Analysis of Sustainability Reports and In-Store Communication 1 Introduction 2 Literature Review 2.1 The challenge of sustainability from the retailer perspective 2.2 Extant research about sustainability communication by retailers 3 Research Design 3.1 Research method and data collection 3.2 Analytical approach 4 Findings 4.1 General characteristics and readability analysis 4.2 Readability analysis 4.3 Identification and comparison of available data 4.4 Store observations 5 Discussion 5.1 Comparison of the sustainability communication between supermarkets and discounters (RQ1) 5.2 Comparison of results from different research approaches (RQ2) 6 Conclusion 7 References