Triethylaluminum is widely used as a catalyst in the polymerization of olefins, such as ethylene and propylene, to produce plastics like polyethylene and polypropylene. It is a key component in Ziegler-Natta catalysts, which are essential for manufacturing high-density and low-density polyethylene.

In the chemical industry, it serves as a co-catalyst in various organometallic reactions, enabling the synthesis of complex organic compounds. It is also employed in the production of linear alpha-olefins, which are important intermediates in the manufacture of detergents, synthetic lubricants, and plasticizers.

Additionally, triethylaluminum is used in the semiconductor industry for metalorganic chemical vapor deposition (MOCVD) processes to create thin films of materials like aluminum nitride and gallium arsenide, which are critical for electronic and optoelectronic devices.

In rocket propulsion, it acts as a hypergolic igniter, reacting spontaneously with oxidizers to initiate combustion in rocket engines, ensuring reliable and immediate ignition.