Fishing bait is any luring substance used specifically to attract and catch fish, typically when angling with a hook and line. There are generally two types of baits used in angling: hookbaits, which are directly mounted onto fish hooks and are what the term "fishing bait" typically refers to; and groundbaits, which are scattered separately into the water as an "appetizer" to attract the fish nearer to the hook. Despite the bait's sole importance is to provoke a feeding response out of the target fish, the way how fish react to different baits is quite poorly understood.

Fishing baits can be grouped into two broad categories: natural baits and artificial baits. Traditionally, fishing baits are natural food or prey items (live or dead) that are already present in the fish's normal diet (e.g. worms, insects, crustaceans and smaller bait fish), and such baits are both procured from and used within the same environment. Artificial baits, conversely, are not naturally acquired and must involve some kind of production process. These can be processed foods (e.g. bread, cheese, dough, cutlets, fish food or pet food pellets, etc.), commercially made feed mixtures (e.g. boilies), or imitative replica "fake foods" made of inedible materials known as lures (e.g plastic worm, swimbaits, spoons, stickbaits, hybrid spinners or even bionic robot fish). The variety of baits that a fisherman may choose is dictated mainly by the target species and by its habitat, as well as personal preference. Both natural and artificial baits frequently demonstrate similar efficiency if chosen adequately for the target fish. The overall bait type, size and techniques used will affect the efficiency and yield when fishing.

Fishing with baits does come with potential environmental concerns, especially when large quantities of non-native ingredients are involved. A common concern is that some live baits (e.g. crayfish and pond loach) can escape and become invasive species, or have the potential to spread diseases or serve as vectors for parasites (e.g. zebra mussel). It is also known that the use of artificial edible baits (especially groundbaits) can potentially cause eutrophication in the local water, which may lead to harmful algal blooms. Using inedible lures, on the other hand, is associated with the issues of littering or loss of said lures, which typically do not biodegrade and can cause problems for the ecosystem, especially if ingested by wildlife. Many materials used to make lures, such as lead (ubiquitous in jigheads), plastics and paint, can degrade after prolonged exposure to the elements and release harmful toxic heavy metals, volatile organic compounds and microplastics that are harmful to the environment.

The natural bait angler, with few exceptions, will use a common prey species of the fish as an attractant. The natural bait used may be alive or dead. Common natural baits include worms (most commonly earthworm and bloodworm), leeches (notably bait-leech Nephelopsis obscura), insects (both adults and larvae), minnows, frogs, salamanders and crayfish. Natural baits are effective due to the lifelike texture, odor and color of the bait presented. Studies show that natural baits like croaker and shrimp are more recognized by the fish and are more readily accepted.

Live bait being used to catch native species is a sustainable and desirable activity in a social and economical aspect, although it is subjected to local regulations which may restrict usage due to ecological and ethical concerns. The availability of live bait and cost factor can inhibit the use of natural baits year round. Anglers can get various live baits from tackle shops at the limitations of price and season. Other ways anglers get natural bait is through usual methods of fishing, e.g. hook and line, traps and casting nets. Once live bait has been obtained, it's important for the angler to keep it alive and fresh for it to be effective. Many anglers opt for a bait pen or small fish cages in order to store and preserve their live bait.

Artificial baits are baits that are not directly acquired via natural means, but are made from other materials via some kind of artificial processing. These can be fish food that are either homemade (e.g. dried food paste) or commercially purchased (e.g. boilies and feed pellets). Homemade artificial baits are often prepared/processed food such as cutlets, offals, dehulled kernels (e.g. pea and corn), dairy products (cheese and curd), bread or doughballs made from various ingredient mixtures (e.g. cooked rice, semolina, cornmeal, bread crumbs and fishmeal, etc.), which can be used to attract omnivorous or even herbivorous fish.

In subtropical lakes such as those in Florida, panfish such as sunfish are such opportunistic feeders that they will even take out-of-the-packet pet food or even household wheat bread as bait. These bread baits are improvised readily from a small amount of bread, often moistened by saliva and sometimes softened by chewing, then squeezed into a small fish bite-sized ball and mounted onto the fishhook.

Lures are inedible artificial baits that are replica "fake foods" designed to mimic the appearance of different prey (usually small fish, as well as worms). Because lures are made of non-biological materials, they do not use scent to attract the target (although chemical attractants can occasionally be added), and instead rely on movements, color/reflections, vibration and noise to attract and "fool" predatory fish into striking.