We present an overview of our recent studies of the gas-phase reaction dynamics of O(3P) with a series of hydrocarbon radicals [allyl (C3H5), propargyl (C3H3), t-butyl (t-C4H9)] as prototypal radical–radical oxidation reactions. High-resolution laser spectroscopy in a crossed-beam configuration was applied to examine the nascent rovibrational state distributions and Doppler profiles of the reactive scattering products. The analyses of the product energy and population distributions demonstrated the existence of unusual dynamic characteristics and competition between the addition and abstraction reaction mechanisms at the molecular level. These features, which are in sharp contrast with those of the oxidation reactions of closed-shell hydrocarbon molecules, are discussed with the aid of ab initio and quantum statistical calculations. Contents PAGE 1. Introduction 614 2. Experiment 615 2.1. Characterization of the molecular beam in the supersonic flash pyrolysis source 616 2.2. Nascent product state distributions from reactive scattering processes 617 3. Ab initio calculations 619 4. Experimental and statistical analysis 620 4.1. Nascent internal state distributions of OH products 620 4.2. Translational energy release 621 4.3. Statistical analysis 621 5. Radical–radical reaction dynamics 623 5.1. Characteristics of the molecular beam in the supersonic flash pyrolysis source 623 5.2. Reaction dynamics of O(3P) with C3H5 626 5.2.1. Ab initio potential energy surface: addition vs. abstraction 626 5.2.2. O(3P) + C3H5 → C3H4 + OH 630 5.2.3. O(3P) + C3H5 → C3H4O + H 635 5.3. Reaction dynamics of O(3P) with C3H3 637 5.3.1. Ab initio potential energy surface 637 5.3.2. O(3P) + C3H3 → C3H2 + OH 640 5.3.3. O(3P) + C3H3 → C3H2O + H 643 5.4. Reaction dynamics of O(3P) with t-C4H9 644 5.4.1. Ab initio potential energy surface 644 5.4.2. O(3P) + t-C4H9 → iso-C4H8 + OH 646 6. Summary 646 Acknowledgments 648 References 649 Supplementary Materials 651