Baal (/ˈbeɪ.əl, ˈbɑːl/), or Baʿal (/bɑː.ɑːl/), was a title and honorific meaning 'owner' or 'lord' in the Northwest Semitic languages spoken in the Levant during antiquity. From its use among people, it came to be applied to gods. Scholars previously associated the theonym with solar cults and with a variety of unrelated patron deities, but inscriptions have shown that the name Baal was particularly associated with the storm and fertility god Hadad and his local manifestations. The Ugaritic god Baal (𐎁𐎓𐎍) is the protagonist of one of the lengthiest surviving epics from the ancient Near East, the Baal Cycle.

Known by epithets like “rider of the clouds” and “Victorious Baal,” he was associated with rain, lightning, wind, fertility, and kingship, and was often depicted in opposition to sea and death deities like Yammu and Mot. Worship of Baal spread throughout the Levant, Egypt, and the Mediterranean via Phoenician colonization, with regional forms such as Baal Hammon in Carthage. The god was also known as "the mighty one", and "the one without equal" ("there is none above him").

The Hebrew Bible includes use of the term in reference to various Levantine deities, often with application towards Hadad, who was decried as a false god. In the Hebrew Bible, Baal appears frequently as a foreign or rival deity, with prophets like Elijah opposing his cult, while in early Israelite contexts, the title may have sometimes referred to Yahweh. Depiction as a false god was taken over into Christianity and Islam, sometimes under the form Beelzebub in demonology.

Classical sources rendered him as Belus. The Quran also references Baal worship, portraying him as a false god opposed by the prophet Elijah.

Baʻal's widely used epithet is "rider (or mounter) of the clouds." (rkb ʿrpt, cf. rkb bʿrbt in Ps. 68:5; Ugaritic rkb ʿrpt.) These are related to Zeus's "gatherer of the clouds" and Yahweh's "rider of the heavens." Like the English word ride, rkb has equine and sexual uses.

The spelling of the English term "Baal" derives from the Greek Báal (Βάαλ) which appears in the New Testament and Septuagint, and from its Latinized form Baal, which appears in the Vulgate. These forms in turn derive from the vowel-less Northwest Semitic form BʿL (Phoenician and Punic: 𐤁𐤏𐤋). The word's biblical senses as a Phoenician deity and false gods generally were extended during the Protestant Reformation to denote any idols, icons of the saints, or the Catholic Church generally. In such contexts, it follows the anglicized pronunciation and usually omits any mark between its two As. In close transliteration of the Semitic name, the ayin is represented, as Baʿal.

In the Northwest Semitic languages—Ugaritic, Phoenician, Hebrew, Amorite, and Aramaic—the word baʿal signified 'owner' and, by extension, 'lord', a 'master', or 'husband'. Cognates include the Akkadian Bēlu (𒂗), Amharic bal (ባል), and Arabic baʿl (بعل). Báʿal (בַּעַל) and baʿl still serve as the words for 'husband' in modern Hebrew and Arabic respectively. They also appear in some contexts concerning the ownership of things or possession of traits.

The feminine form is baʿalah (Hebrew: בַּעֲלָה; Arabic: بَعْلَة), meaning 'mistress' in the sense of a female owner or lady of the house and still serving as a rare word for 'wife'.