By increasing the price of imports, tariffs can protect domestic manufacturers. They can also serve to punish foreign countries for unfair trade practices such as subsidizing their exporters or selling products at unfairly low prices.

Tariffs are generally used to raise government revenue and to protect sensitive or nascent national industries from international competition.

Under the WTO, tariffs can also be used or increased to offset dumping or other measures deemed contrary to international trade rules.

The negative aspects of tariffs are more frequently examined, as they outweigh the positive aspects in magnitude. From a macroeconomic perspective, tariffs engender a deadweight loss. The imposition of tariffs results in a reallocation of economic gains from foreign producers and domestic consumers to domestic producers and the government. Nonetheless, domestic producers and the government do not experience an increase in economic gains that is commensurate with the losses incurred by foreign producers and domestic consumers. A portion of these gains is forfeited as a result of diminished economic efficiency. Accordingly, even though it's positive aspects do occur, tariff can only imposed temporarily.

Tariffs can have positive effects such as protecting nascent industries, reducing trade deficits, generating government revenue, and increasing domestic employment in targeted sectors, although these benefits are often short-term and may come at the expense of broader economic welfare.