Viaredssjön, Lake in Borås Municipality, Sweden

Viaredssjön is a lake in western Sweden situated between the municipalities of Borås and Bollebygd. The water body features heavily forested shores and serves as a natural focal point for outdoor recreation in the region.

Peat extraction began in 1908 in a bog south of the lake; the peat was carried by barges across Viaredssjön to Hultafors for transfer to the railway. The barges were initially towed by rowing boats or ropes from land, later by motorboats, until lorries replaced them in 1920. The former tugboat then ran booked pleasure trips between 1920 and 1927, especially to the Lyckebo guesthouse.

The lake's sailing club, Viaredssjöns Segelsällskap, dates from the mid-20th century and was very active into the 1980s; in the mid-1970s over twenty Triss dinghies raced in its regattas, and the club trained Olympic-class sailor Martin Andersson. In summer, Brisar Strand sells ice cream and sweets at the larger beach in Sandared and rents out boats.

The southern shore has long stretches of undeveloped shoreline, while the northern side at Sandared and Sjömarken is built up almost to the water. The bay at Sjömarken is shallow with more aquatic plants. Brisar Strand sells ice cream and sweets at the main beach in Sandared in summer and rents out boats.

The watershed area of Viaredssjön spans 69.2 square kilometers, contributing to the regional water system between Gothenburg and Borås.