Two-wheel tractor or walking tractor are generic terms understood in the USA and in parts of Europe to represent a single-axle tractor, which is a tractor with one axle, self-powered and self-propelled, which can pull and power various farm implements such as a trailer, cultivator or harrow, a plough, or various seeders and harvesters. The operator usually walks behind it or rides the implement being towed. Similar terms are mistakenly applied to the household rotary tiller or power tiller; although these may be wheeled and/or self-propelled, they are not tailored for towing implements. A two-wheeled tractor specializes in pulling any of numerous types of implements, whereas rotary tillers specialize in soil tillage with their dedicated digging tools. This article concerns two-wheeled tractors as distinguished from such tillers.
Power tiller" can be understood as a garden tiller/rototiller of the small (3–7 hp or 2.2–5.2 kW) petrol/gasoline/electric powered, hobby gardener variety; they are often sold as a rotary tiller, though the technical agricultural use of that term refers solely to an attachment to a larger tractor. Alternatively, the terms "power tiller" or "rotary tiller" are always understood in Asia and elsewhere to be rubber- or iron-wheeled, self-propelled machines of 5–18 hp (3.7–13 kW) and usually powered by heavy-duty single-cylinder diesel engines (many Asian countries historically have had a high luxury tax on petrol/gasoline). Adding to the nomenclature confusion, agricultural engineers like to classify them as single-axle tractors. For clarity, the rest of this article refers to the self-propelled, single-axle, multi-attachment tractive machines as two-wheel tractors.
For production agriculture, past and present, two-wheel tractors are offered with wide range attachments such as rotovators, moldboard, disc-plow and spike-tooth harrows, seeders, transplanters, and planters. Even zero till/no-till planters and seeders have become available. In plant protection two-wheel tractor attachments consist of various inter-cultivators and sprayers. For harvesting mowers, reaper/grain harvesters, reaper-binders, and even combine harvesters are available for them. For transport, trailers with capacities from 0.5 to 5 plus ton cargoes are available, meaning they can execute practically all of the chores done by larger 4-wheel tractors.
This confusion over, or perhaps just ignorance of the utility of 2-wheel tractors persists even at research and institutional levels. The United Nation's Food and Agriculture Organization's own statistical database, FAO Stat  gauges levels of agricultural mechanization by numbers of 4-wheel tractors and ignores completely the fact that 2-wheel tractors often perform much, or even exactly, the same work as done by 4-wheeled models. By using FAO's statistics, international donors and agricultural research and development centres assume, as Bangladesh and Sri Lanka have very few 4-wheel tractors, that they are completely unmechanized compared to (e.g.) India, which has a large population of them (besides 100,000 two-wheel tractors). Yet, when two-wheel tractors are included, Bangladesh and Sri Lanka are the most highly mechanized countries in south Asia in terms of area farmed using mechanized tillage.