"There were strong debate and disagreement on some issues, but after detailed discussions between both leaders and our teams we were able to find common ground and draw up a communique which reflected these discussions and the agreements we reached," May said at a parliament session.
May thanked Canadian Prime Minister Justin Trudeau for organizing the summit.
The UK prime minister expressed disappointment over US decision to tax steel and aluminum imports from the European Union.
"The loss of trade through tariffs undermines competition, reduces productivity, removes the incentive to innovate – and ultimately makes everyone poorer. And in response, the EU will impose countermeasures," May said.
Jeremy Corbyn, the head of the opposition and the leader of Labour party, denounced the summit as a failure caused by Trump. Corbyn also criticized the prime minister over her stance on Brexit, hurting the UK economy.
The United States imposed a 25-percent tariff on steel imports and a 10-percent duty on aluminum imports in March but suspended the tariffs on Canada, Mexico, several other states and the European Union in order to attempt to negotiate a better deal. However, on May 31, the United States reintroduced tariffs on imports from Canada, Mexico and the European Union.