Achziv (Hebrew: אַכְזִיב ʾAḵzīḇ) or Az-Zeeb (Arabic: الزيب, romanized: Az-Zīb) is an ancient site on the Mediterranean coast of northern Israel, between the border with Lebanon and the city of Acre. It is located 13.5 kilometres (8.4 mi) north of Acre on the coast of the Mediterranean Sea, within the municipal area of Nahariya. Today it is an Israeli national park.

Excavations have unearthed a fortified Canaanite city of the second millennium BCE. The Phoenician town of the first millennium BCE is known both from the Hebrew Bible and Assyrian sources. Phoenician Achzib went through ups and downs during the Persian and Hellenistic periods. In early Roman times the town, known as Acdippa, was a road station. The Bordeaux Pilgrim mentions it in 333-334 CE still as a road station; Jewish sources of the Byzantine period call it Kheziv and Gesiv. There is no information about settlement at the site for the early Muslim period. The Crusaders built a new village with a castle there. During the Mamluk and Ottoman periods a modest village occupied the old tell (archaeological mound).

In modern times the site was known as the Palestinian town of Az-Zeeb, with a population of almost 2,000. It was depopulated during the Haganah's Operation Ben-Ami, on May 14, 1948, the last day of the British Mandate for Palestine.

The sole permanent resident of Achziv since declaration of the State was Eli Avivi (1930–2018), an Israeli photographer and micronationalist who hosted visitors to the legally disputed micronation of "Akhzivland", a small stretch of beach where he lived since 1975 until his death.

Mentioned in the Bible by its ancient name Achzib, evidence of human settlement at the site dates back to the 18th century BCE. During the Roman period (and in classical literature) the imperial authorities called it Ecdippa, Ecdeppa, or Ecdippon. By the early Middle Ages, the Arab name for the village "Az-Zeeb", or "al-Zib" (Arabic: الزيب meaning 'trickster') was locally in common usage. Az-Zeeb is a shortened form of the site's original ancient Canaanite/Phoenician name, Achzib.

Human settlement at the site dates to as early as the 18th century BCE; and by the 10th century BCE it was a walled town. A tell excavated between 1941–44 and 1959-1964 found evidence of settlement from the Middle Bronze Age II, through the Roman Empire and the Early Middle Ages. Achziv was the first fortified settlement found at the site by archaeologists.

In the Middle Bronze IIA (MBIIA), remains are found at Phase N5 with features including child burials in storage jars below floors.

At the transition from MBIIA to MBIIB, the settlement was subject to a violent destruction.