Carbon dioxide (CO2), as a waste of manufacture, is a cheap and abundant C1 source. Utilization of CO2 for synthesis of carboxylic acids has been developed. Transition-metal complexes play a key role in catalytic carboxylation reactions employing CO2. This review summarizes recent advances in copper-catalyzed carboxylation reactions using CO2. The contents are arranged based on various substrates: organometallic reagents, aryl iodides, sodium sulfinates, terminal alkynes, arenes, heteroarenes, and unsaturated substrates.