Jewish settlers wielding clubs and stones have attacked a group of Palestinian labourers entering the West Bank settlement of Nahliel.
Palestinians are often employed on Jewish settlements
Israeli police said 30 to 40 Jewish seminary students attacked eight men employed early on Thursday.
Three of the Palestinians needed hospital treatment in nearby Ramallah after the assault which left at least one man unconscious.
Israeli police said they were investigating the incident.
"By the time officers reached the settlement, which is relatively isolated, the assailants had escaped," a police spokesman said.
One of the victims said he had no idea why the assault took place.
"One of my colleagues fell down and they beat him, said Muki Shakarni, "I tried to protect him but they beat me. I lost consciousness and only came round in the hospital".
Jewish settlements often employ local Palestinians as labourers despite tensions between Palestinians and settlers.
The international community considers all settlements in Gaza and the West Bank, including East Jerusalem, as illegal under international law, though Israel disputes this.