Hundreds gathered near Istanbul's central Taksim Square after the bombing in the mostly Kurdish border town of Suruc which killed at least 30 people.
Some chanted slogans against President Tayyip Erdogan and the ruling AK Party, including: "Murderer Islamic State, collaborator Erdogan and AKP."
Turkey's Kurds have been enraged by what they see as Ankara's failure to do more to stop Islamic State. The PKK Kurdish militant group earlier said it held the government responsible for Monday's attack, saying Ankara had "supported and cultivated" Islamic State against the Kurds in Syria.
The demonstration in Istanbul had largely been peaceful, but some protesters threw bottles at police, the witness said.