Did Jesus die on the cross, or does the Quran deny it?

Yes - Jesus really died by crucifixion, and on this point the historical evidence runs strongly one way, even though the Quran on its dominant reading denies it. Surah 4:157 says "they did not kill him, nor did they crucify him, but it was made to appear so to them," which classical Islamic tradition often reads as a substitution - God rescuing his prophet while another was crucified in his place (though some Muslim scholars read it more subtly, as denying that Jesus' enemies truly triumphed rather than denying his death outright).

On the historical question the evidence is unusually one-sided. Jesus' death by crucifixion under Pontius Pilate is regarded by historians across the spectrum as among the most certain facts we have about him. The agnostic scholar Bart Ehrman calls it as sure as anything historical can be, and it is attested not only in the Gospels but in non-Christian sources like the Roman historian Tacitus. Crucifixion was also the last thing early followers would invent about a Messiah - a crucified Messiah was a scandal, not a selling point.

So the tension is real and should be named without triumphalism. The Quran, on its usual reading, sets aside an event that the historical record attests as firmly as almost anything from antiquity. That does not settle every question of faith, but on this particular point the historian and the Gospel writers stand together: Jesus really did die on a Roman cross.