Credit rating agency Moody's has upgraded Ireland's rating to A2.
Irish senior unsecured bond, programme ratings and commercial paper ratings were also upgraded.
The outlook on the ratings was also changed to 'stable' from 'positive'.
Moody's says the key drivers for the upgrade were that the economy "continues to grow at a faster-than-expected pace."
"Brexit remains a downside risk to growth, but the broad-based nature of the recovery and the flexibility of the Irish economy provide some degree of resilience".
The agency also says that the improvement in Irish fiscal metrics has continued, "with the budget position approaching balance and the public debt ratio continuing its rapid decline."
Moody's says it expects these positive fiscal and debt trends to continue "in the coming years."
The agency has also upgraded the National Asset Management Agency (NAMA) to A2 from A3.
Moody's says: "NAMA's ratings are aligned with those of the Irish sovereign, given that NAMA's debt obligations are explicitly guaranteed by the Republic of Ireland. The outlook on the ratings was also changed to stable from positive."
And Ireland's long-term local and foreign-currency bond and deposit ceilings remain unchanged at 'AAA'.
Responding to the upgrade Frank O'Connor, the National Treasury Management Agency (NTMA)'s director of debt management, said: "This upgrade is welcome news and reflects the ongoing improvements in Ireland's debt dynamics.
"The upgrade brings Ireland's rating above the mean 'A' range across the main ratings agencies, which is a significant positive for investors who look to the average".