As regulation increasingly results from the interplay of a wide array of different actors operating at different levels, it has become crucial to focus on how these constellations of regulatory actors operate. Although this research field presents huge potential for theoretical development, we still lack the measurement techniques to allow systematic comparative research. We contribute to filling this gap with four indices measuring crucial characteristics of multi-actor regulatory arrangements: (i) the scope of organizational proliferation; (ii) the extent of coordination between regulatory actors; (iii) the amount of influence that each individual regulatory actor has on the sector regulation; and (iv) the extent to which the regulatory influence is concentrated in the hands of one or a few actors. We argue that our indices are sufficiently systematic, reliable, and flexible to be applied in a variety of research contexts relating to multi-level and multi-actor regulatory governance.