How does a social enterprise pursue its ethical mandate of social impact growth while navigating the perils of the most vulnerable stage in a venture’s life—scaling up? We observe a small inclusivity social enterprise attempting to scale up rapidly to create equality for people with disabilities throughout the world. Our embedded, ethnographic study is terminated with the venture’s unfortunate demise after their dramatic effort to scale up failed. By examining scaling decision-making and conflicts around creation reasoning longitudinally, our study identifies (...) over-use of effectual logic—a creation reasoning type considered more ethical and more appropriate for high-innovativeness contexts than causal logic—as a major factor in the venture’s failure. From this insight, we extend the parameters of effectuation theory to scaling up and dimensionalize its ethical implications. Guidance for social entrepreneurs to scale up successfully while maintaining ethical integrity is also provided. (shrink)