A bucket toilet is a basic form of a dry toilet whereby a bucket (pail) is used to collect excreta. Usually, feces and urine are collected together in the same bucket, leading to odor issues. The bucket may be situated inside a dwelling, or in a nearby small structure (an outhouse).

Where people do not have access to improved sanitation – particularly in low-income urban areas of developing countries – an unimproved bucket toilet might be better than open defecation. They can play a temporary role in emergency sanitation, e.g. after earthquakes. However, the unimproved bucket toilet may carry significant health risks compared to an improved sanitation system. The bucket toilet system, with collection organised by the municipality, used to be widespread in wealthy countries; in Australia it persisted into the second half of the 20th century.

Once the basic bucket toilet has been "improved", it evolves into a number of different systems, which are more correctly referred to as either container-based sanitation systems, composting toilets, or urine-diverting dry toilets.