Are insects halal to eat?

Locusts: clearly allowed

Abdullah ibn Abi Awfa said, "We went on seven military expeditions with the Prophet ﷺ and we used to eat locusts with him" (Sahih al-Bukhari 5495). Scholars agree that locusts are halal and, like fish, do not need slaughter. Grasshoppers of the locust type are treated the same way by many scholars.

Other insects: the "good and impure" rule

The Quran describes the Prophet's ﷺ role in this way:

The majority (Hanafi, Shafi'i and Hanbali) understood "the evil" (al-khaba'ith) to include creatures that people with normal taste find repulsive, such as worms, beetles, flies, ants and cockroaches. So for them, eating insects other than locusts is not allowed. The Maliki school holds that insects may be eaten if they are not harmful and are killed with the intention of eating, so mealworms or crickets could be permitted in that view. Both positions are held in good faith. A similar debate covers snails and frogs. See Can I eat snails and frog legs as a Muslim?

Insect protein in modern food

• Cricket flour and protein bars: sold in the UK, EU and USA, mostly from crickets and mealworms. Follow your school; if in doubt, skip them.
• Carmine (E120, cochineal): a red colour from crushed insects, used in sweets, yoghurt and lipstick. Many scholars and halal bodies allow it because it is a tiny additive and not eaten as food; others avoid it. See Are E-numbers halal?
• Shellac (E904): a glaze from an insect resin on sweets and fruit. Most halal authorities accept it.
• Honey: made by bees but not an insect itself; it is halal and praised in the Quran.

Accidental bugs

A tiny insect that falls into your food or flour by accident doesn't make the whole meal haram. Remove it if you can and carry on. Islam doesn't ask you to inspect every grain. For the general rules on what Muslims eat, see What can Muslims eat?