Waldemar Johannes Aspelin (Koski, Perniö, (now Salo), Finland, 26 September 1854 – Helsinki, 10 November 1923) was a Finnish architect.

[1] Waldemar Aspelin was born in the mining community of Koski, about halfway between Helsinki and Turku, then in the Grand Duchy of Finland, part of the Russian Empire.

[3] Aspelin designed residential and commercial buildings in different parts of the old inner city of Helsinki; for example, on Puistokatu, Bulevardi and Yrjönkatu.

The number of stone buildings in Helsinki tripled from 1880 to 1910, as the modern city underwent rapid growth to reach a population of around 100,000 inhabitants that replaced what had been an agrarian trading post.

The Consul Rothe House [ru] (1897–1900) is a significant part of the skyline of the city facing the sea, between Yuzhny Val, Podgornaya and Vyborgskaya streets.

According to the art historian Evgeny Evgenievich Kepp, the architect unsuccessfully insisted on the demolition of the historic Round Tower, which obscures the neo-Renaissance facade of the bank.

Later studies do not find documentary evidence of this, claiming that Berndt Ivar Aminoff was the architect who insisted upon the tower's demolition.

[6] Aspelin is a representative of the revival styles of the nineteenth century, but his later buildings can sometimes be described as Art Nouveau (often called Jugendstil).