Neutron diagnostics is discussed as a supplier of alpha-particle information on the burning deuterium-tritium plasmas of next-step tokamaks such as the International Thermonuclear Experimental Reactor/Next European Torus (ITER/NET), Ignitor, and the Burning Plasma Experiment (BPX). Conceptual studies for such neutron measurements with neutron cameras and spectrometers are presented, and the potential information output is identified and assessed. Examples are given as to where direct alpha-particle information can be provided, and the. relevance of neutron data as a source of indirect information is illustrated in view of the envisaged quality, scope, and availability of neutron measurements for various plasma conditions. Also discussed is how neutron diagnostics can serve as a plasma condition monitor for burn control purposes besides bringing experimental insight on the physics of fusion plasmas with a significant fast alpha-particle population.