<p>Emissions reductions are needed across the iron and steel, cement and primary chemical sectors, as they contribute greatly to global carbon emissions (~17% of emissions globally in 2021). However, these sectors are hard to abate owing to complex production processes, a heavy reliance on fossil fuels and/or a lack of alternative technologies. In this Perspective, we discuss technology opportunities and gaps for deep decarbonization in these sectors. Decarbonization strategies and technologies in this sector can broadly be categorized as energy efficiency improvements, electrification, recycling and demand-side technologies, bioenergy, carbon capture and storage, hydrogen usage and feedstock substitution. Technological readiness varies between and within each set of approaches and — along with regional and plant-level factors — impacts the feasibility of deployment. These technologies have abatement costs and products made using low-carbon and zero-carbon technologies often carry green premiums, but with substantial variability between products and technologies. Decarbonization strategies should prioritize more readily available approaches such as energy efficiency improvements, recycling and electrification in the short term. In the longer term, carbon capture and storage and clean hydrogen will require substantial investment if they are to be broadly applied. Future efforts must address challenges related to resource availability, high energy consumption and economic costs of decarbonization technologies.</p>