The quarterly growth in the country's gross domestic product, the broadest measure of economic performance, slowed from a 0.9 percent on-quarter growth in the first three months of the year, according to the Bank of Korea (BOK).
From a year earlier, Asia's fourth-largest economy expanded 3.6 percent in the April-June period after advancing 3.9 percent on-year in the previous quarter.
The figure marks the first slowdown since the third quarter of 2012 when on-year growth slowed to 2.1 percent from 2.4 percent in the second quarter.
The Korean economy is widely seen as on a modest recovery track as firm exports lend support. The Sewol ferry accident in mid-April, however, weighed on domestic demand as the tragic sinking sapped consumer sentiment.
Earlier this month, the central bank trimmed its growth outlook for the year to 3.8 percent from 4 percent, factoring in the impact of the ferry accident that left more than 300 dead or missing.
The BOK also kept the base rate steady at 2.5 percent for a 14th straight month in July, citing increasing downside risks facing the economy.
Exports, the main engine for Asia's fourth-largest economy, climbed 1.9 percent on-quarter in the second quarter, accelerating from a 1.5 percent expansion three months earlier.
Private spending contracted 0.3 percent from the previous quarter, reversing from a 0.2 percent growth in the first quarter. It also marked the first contraction since the first quarter of 2013 when it slipped 0.1 percent.
Facility investment gained 1.3 percent, turning around from a 1.9 percent contraction in the previous quarter. Construction investment inched up 0.6 percent, slowing from a 5.1 percent on-quarter gain in the previous quarter, according to the data.(Yonhap)