Synthetic organic polymers, specifically high-volume thermoplastics in commodity products, are ubiquitous in industrialized societies. The rapidly growing market of these thermoplastics (e.g., polypropylene) has created huge amounts of plastic waste globally. The heavy reliance of the global economy on fossilized feedstocks (e.g., petroleum) has necessitated the search for alternative energy sources. Polypropylene (PP) has a hydrocarbon backbone that can be depolymerized by thermal cracking under pyrolytic conditions into diesel-range fuels. The process forms liquid fuels, carbonized solids (char), and combustible gases. The end-of-life PP is one of the most common plastic waste (volume-wise) found in municipal solid waste (MSW). The PP wastes can be pyrolyzed to produce liquid fuels suitable for furnaces and diesel engines. However, the composition of polypropylene pyrolysis oil (PPO) must be studied to optimize the pyrolytic process conditions and also to design suitable upgrading technology. The present study reports an extensive characterization of the pyrolysis oil obtained by the industrial-scale pyrolysis of end-of-life PP. PPO produced from shredded PP is pyrolyzed in a semi-continuous screw kiln reactor at temperatures in the range of 600–700 °C and analyzed using Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance spectroscopy (NMR) and gas chromatography-mass spectrometry (GC-MS) analysis. The 1H-NMR analysis revealed that the PPO sample contained 58.88, 27.41, and 13.74 vol% of paraffins, olefins, and aromatics respectively. GC-MS analysis showed the presence of high molecular weight compounds in PPO that may result in more CO2 and CO emissions than conventional diesel fuel. Many of the physicochemical and thermal properties of PPO were similar to that of diesel. However, the poor storage and thermal stability of PPO warrants suitable upgrading for better combustion and performance when used in diesel engines.