Arboldswil is a municipality in the district of Waldenburg in the canton of Basel-Country in Switzerland.
Arboldswil is first mentioned in 1226 as Arboldswilre.
Arboldswil has an area, , of . Of this area, or 51.1% is used for agricultural purposes, while or 41.4% is forested. Of the rest of the land, or 6.3% is settled (buildings or roads).
Of the built up area, housing and buildings made up 3.4% and transportation infrastructure made up 2.6%. Out of the forested land, 39.4% of the total land area is heavily forested and 2.0% is covered with orchards or small clusters of trees. Of the agricultural land, 9.8% is used for growing crops and 32.5% is pastures, while 8.9% is used for orchards or vine crops.
The municipality is located in the Waldenburg district, on a plateau in the Jura Mountains between the Waldenburger and Reigoldswiler valleys.
The blazon of the municipal coat of arms is Azure, a tower embattled argent masoned sable issuant from a mount of three coupeaux vert, in chief the sun in its splendour or.
Arboldswil has a population () of . , 4.6% of the population are resident foreign nationals. Over the last 10 years (1997–2007) the population has changed at a rate of 5.3%.
Most of the population () speaks German (454 or 92.1%), with Portuguese being second most common (16 or 3.2%) and French being third (5 or 1.0%).
the gender distribution of the population was 50.5% male and 49.5% female. The population was made up of 494 Swiss citizens (94.5% of the population), and 29 non-Swiss residents (5.5%) Of the population in the municipality 187 or about 37.9% were born in Arboldswil and lived there in 2000. There were 143 or 29.0% who were born in the same canton, while 91 or 18.5% were born somewhere else in Switzerland, and 67 or 13.6% were born outside of Switzerland.
In there were 8 live births to Swiss citizens and were 2 deaths of Swiss citizens. Ignoring immigration and emigration, the population of Swiss citizens increased by 6 while the foreign population remained the same.