The event, part of the state visit of the Irish president Michael D Higgins, was held to recognise the contribution of British and Irish individuals who have furthered co-operation, enterprise and culture between Britain and Northern Ireland.
Guests included First Minister of Northern Ireland Peter Robinson, Sinn Fein's Martin McGuinness and Theresa Villiers, Secretary of State for Northern Ireland.
The Queen and the Duke of Edinburgh greeted and chatted to the guests, who included MPs and MEPs from Northern Ireland, and medal-winning Olympic and Paralympic athletes.
Mr McGuinness shook hands with the Queen and congratulated her on her role in peace-making in Ireland.
He said: "The Queen's visit to Dublin and how she conducted herself were all hugely impressive.
"She had many reasons not to meet me, and me her, but I think we've risen above that and seen the contribution that these big acts of reconciliation can have.
"I'm overjoyed for the president. The week will be noted for its spirit of generosity and peacemaking."
The afternoon reception was followed by a Ceiliuradh (Celebration) at the Royal Albert Hall in London — an Irish cultural concert of music, spoken word and dance.