Commitment to a strategy is a significant, yet under-researched area of relationships between buyer and supplier organisations. Specifically, the key drivers and outcomes of strategy commitment in the context of inter-organisational relationships have been given little consideration in extant literature. The factors buyers consider significant with regard to strategy commitment is an important issue; suppliers that understand this are likely to gain commitment to a strategy from a buyer, and buyers might manage relationships more effectively. Subsequently, once a buyer is committed to a strategy, they are likely to invest resources into the strategy to aid in its success. Ultimately, the level of commitment a buyer places in a strategy is believed to impact on the degree of investment a buyer makes into a strategy, which in turn impacts on the overall success of a strategy. Much of the strategy literature considers strategy commitment and success from a macro perspective, examining the effects of market performance and orientation, and environmental factors on a firm's commitment to, and the ensuing success of a new strategy or product. Absent from these theories, however, is detailed consideration of strategy commitment and success from a micro perspective; for example, the inter-organisational and strategy-specific factors that affect a buyer's decision to implement a strategy proposed by a supplier. While several studies examine micro characteristics, albeit to a limited degree, their primary focus is on factors such as organisational commitment and "buy-in" to a proposed strategy. In contrast, few studies consider the combined impact of inter-firm relationship characteristics (e.g., trust and relationship commitment), strategy and inter-organisational fit, and strategy characteristics on the commitment to and success of strategies developed in buyer-supplier contexts. The specific context in which this study is centred is advertiser-advertising agency relationships. Essentially, this study examines the impact of relationship characteristics (i.e., trust and commitment) and fit issues (i.e., campaign and inter-organisational) on campaign commitment. Also considered are the relationships between campaign commitment and campaign investment, and ultimately, campaign success. Conceptualising and testing this process model is central to this thesis. The potential moderating impacts of campaign characteristics (i.e., creativeness and radicalness) on the relationships studied are also tested. Five research hypotheses are advanced that describe the process model. A survey-based research approach is taken; data is collected from seventy advertisers drawn from a national sample of Australian advertisers. The data is subsequently analysed using structural equation modelling to test the empirical model and hypotheses. Support is found for three of the five core hypotheses, with campaign commitment emerging as the key predictor of campaign success. These findings form the basis for several theoretical and practical implications relevant to marketing scholars and practitioners.