Which Surah was revealed at last?

Answer:

All praise is due to Allah. The final Surah revealed in the Quran was Surat al-Nasr (“When there comes the Help of Allah (to you, O Muhammad against your enemies) and the Conquest (of Makkah)” [al-Nasr 110:1 – interpretation of the meaning]). This perspective is attributed to Ibn `Abbas (may Allah be pleased with him).