Al Jazeera's Rula Amin, reporting from Beirut, said the rocket attack was not the first on Israel from Lebanon.
Less than a week ago, a similar attack took place when a couple of rockets also fired from southern Lebanon hit Israel.
There was no immediate claim of responsiblity, and Hezbollah denied any involvement.
Israel and the Hezbollah fought a 34-day war in 2006, after fighters from the Lebanese Shia movement seized two Israeli soldiers.
Wednesday's attack occured on the 19th day of the Israeli offensive in Gaza that has left almost 1,000 Palestinian dead.