Understanding, measuring, and leveraging the similarity of binaries (executable code) is a foundational challenge in software engineering. We present a notion of similarity based on provenance—two binaries are similar if they are compiled from the same (or very similar) source code with the same (or similar) compilers. Empirical evidence suggests that provenance-similarity accounts for a significant portion of variation in existing binaries, particularly in malware. We propose and evaluate the applicability of classification to detect provenance-similarity. We evaluate a variety of classifiers, and different types of attributes and similarity labeling schemes, on two benchmarks derived from open-source software and malware respectively. We present encouraging results indicating that classification is a viable approach for automated provenance-similarity detection, and as an aid for malware analysts in particular.