We argue that positive employee relations effectively serves as an intangible and enduring asset, and may, therefore, be a source of sustained competitive advantage at the firm level. We survey a number of measures of firm-level performance and conceptualize how each measure is likely to be affected by highly positive firm-level employee relations. We then empirically investigate whether positive employee relations is related to firm performance, focusing on publicly traded firms included in the “100 Best Companies to Work for in America.” The relative performance of these “Best Companies” is examined via comparisons to both companies in the broad market and a group of matched firms. Our analyses suggest that companies on the 100 Best list enjoy not only stable and highly positive workforce attitudes, but also performance advantages over the broad market, and in some cases, over the matched group.