Four people suffered shock and were treated at the city's post-traumatic stress center. Two buildings were damaged.
Sderot is on heightened alert after a senior Islamic Jihad chief was killed by the Israeli Defense Forces in Gaza Friday.
Sderot's streets were empty when the rocket hit early Saturday due to fear of more attacks and because of the Sabbath.
The city's security chief, Eli Ben Maman, told Ynet, "This is a ritual that's been repeating itself for seven years now. The IDF strikes in Gaza, and we get hit by Qassams. It takes them some time to get organized, but they (the Palestinians) fire the Qassams when they can. If we're not hit today, we'll be hit tomorrow morning."
The region's police forces plan to meet Saturday evening to reevaluate the situation in the area.
Weekend of violence
Friday morning four Qassam rockets were fired from northern Gaza. Two landed near a kibbutz in the Sha'ar Hanegev regional council, damaging the community's garage.
Another rocket landed in a kibbutz near Ashkelon, causing damage to a building. The fourth rocket landed in Palestinian territory.
In response to the rocket attacks the IDF targeted a senior Islamic Jihad member on Friday evening while he was riding his motorcycle in the southern Gaza Strip town of Khan Younis.
Following the targeted killing, Al-Aqsa Martyrs' Brigades spokesman Abu Ahmed told Ynet that "our response will come soon. Israelis should prepare for additional rockets and suicide bombings."
The man killed in the airstrike was identified by Palestinians as Fadi Abu Mustafa. According to IDF officials, he was involved in planning terror attacks against Israeli targets.
A senior Islamic Jihad member told Ynet that Abu Mustafa was a top member of the al-Quds Brigades, the organization's military wing, in the southern Strip.
A few hours earlier the IDF shot and killed two suspects moving suspiciously near the border fence in north Gaza, which according to Palestinians were two 8 and 11-year-old children.
Israeli military officials said the two Palestinians killed were teenagers, 17-18 years old, crawling in an area Palestinians are banned from entering. The two ignored the soldiers who called on them to stop, the army said.
The Palestinians claimed that the children were looking for aluminum and iron to sell in the market. The soldiers assumed that the two Palestinians were attempting to plant an explosive device in the area and fired at them.
Ali Waked contributed to the report