In a developing country context, a policy to promote adoption of common environmental content for corporate codes of conduct (COCs) aspires to meaningful results on two fronts. First, adherence to COC provisions should offer economic benefits that exceed the costs of compliance; i.e., companies must receive a price premium, market expansion, efficiency gains, subsidized technical assistance, or some combination of these benefits in return for meeting the requirements. Second, compliance should produce significant improvements in environmental outcomes; i.e., the code must impose real requirements, and monitoring and enforcement must offer sufficient incentives to prevent evasion. With those goals in mind, we explore options for establishing common environmental content in voluntary COCs. Because the benefits of a COC rest on its ability to signal information, we ground our analysis in a review of experiences with a broad range of voluntary (and involuntary) information-based programs: not only existing corporate COCs, but also the International Organization for Standardization (ISO) family of standards, ecolabels, and information disclosure programs. We find some important tradeoffs between harmonization, applicability, feasibility, and efficacy.