This article examines the names of days of the week (панядзелак, etc.) in the pages of the second Belarusian-language newspaper „Nasza Niwa” („Naša Niwa”), published in Vilna (Vilnius) in 1906–1915 (from December 1906 to January 1913 it was the only Belarusian-language newspaper in the world). The article focuses in particular on the first year of publication of this newspaper. Materials from the subsequent years of publication of this newspaper are also used for comparison. This data is compared with dialect materials from the second half of the 19th – early 21st centuries and with dictionaries of the modern Belarusian literary language. The article uses data from Polish, Old Russian, Church Slavonic, and other languages for diachronic and areal analysis. The aim of the article is to compare all lexical units that functioned in „Nasza Niwa” and in dialects in order to determine which forms were appropriate for the literary language of the early 20th century and what application they have in contemporary literary Belarusian. The issues raised in the article have not yet been considered in scholarly work. This study uses the following research methods: linguistic description, the retrospective method (in reconstructing vocabulary from the turn of the 19th and 20th centuries), the statistical method (in analyzing extensive material from newspapers), etc. Based on the analyzed material, this article concludes that, in general, the names of the days of the week in the Belarusian literary language of the early 20th century coincide with the norm of the early 21st century, despite the fact that, both in „Nasza Niwa” and in the dialects, there were variants of the names of the II (аўторак – уторак), IV (чацвер – чэцвер) and V (пятніца – пяток) days of the week. On the other hand, the variants of the name of the VI (субота) day of the week – сыбота, сабота – present in the dialects were not found in the pages of „Nasza Niwa” or in academic dictionaries of the early 21st century.