Later in 2006, he received his first senior Northern Ireland call-up on a post-season trip to the United States to play friendly games against Romania and Uruguay. Lafferty scored his first Northern Ireland goal in an away friendly against Finland the following year. He featured predominantly as the second striker alongside David Healy during Northern Ireland's Euro 2008 qualification group, and he scored his first competitive international goal in a 4–1 victory over group minnows Liechtenstein. He then secured a 1–1 draw away to Sweden, scoring Northern Ireland's equaliser in the second half.