The Queen praised the Welsh Assembly on its record since the advent of devolution during the royal opening of the fourth assembly on 7 June 2011.
In her address to the assembly, Queen Elizabeth II congratulated the assembly on the good work it had already been done but said that a new legislative system marked a new era for the institution.
The Queen said that the Assembly had a "well-deserved reputation for diligence and competence."
Following a successful referendum on full law-making powers, the fourth assembly is able to pass legislation on devolved matters without requiring prior consent from Westminster.
"The performance of the Assembly in discharging these new responsibilities will be closely scrutinised here in Wales and elsewhere," she said.
First Minister Carwyn Jones AM echoed the Queen's sentiments when he said that the assembly has "the powers to make a difference."
"All the people of this country, irrespective of who they voted for, or even if they did not vote at all, are entitled to expect that their government will try to serve their interests in good faith, and, as First Minister, that is my pledge," he added.
Plaid Cymru leader Ieuan Wyn Jones AM was notable for his absence as the leaders of the other Welsh parties greeted the Queen's arrival.
Four Plaid Cymru AMs did not attend the event on principle, including Bethan Jenkins AM, Lindsay Whittle AM, Llyr Huws Gruffydd AM and Leanne Wood AM.
Read this in Welsh.