This report provides an overview of commercial and developing technologies for the by-product and on-purpose production of propylene, the second most used chemical in terms of global volumes after ethylene. By-product propylene technologies include naphtha cracking, conventional and enhanced fluid catalytic cracking (FCC) of vacuum gas oil and atmospheric residue. This is followed by on-purpose propylene technologies that include residual grade propylene fractionation, propane dehydrogenation, metathesis, olefins catalytic conversion/cracking and methanol-based processes. The technoeconomic and carbon intensity analysis of the technologies in four regions (Middle East, United States, Western Europe, and China) are discussed, with coal-based processes included for China. Emerging or developing technologies that have the potential to decarbonize propylene production are also discussed. Cash margins for the commercial technologies by regions are correlated to the carbon intensities (scope 1 and 2), with a breakeven carbon cost analysis for fluidized bed catalytic crackers that are integrated with carbon capture systems. Global propylene capacity by producer is provided.