Lahja Anna-Maija Lehtonen (3 August 1927 Helsinki, Finland – 19 August 2016 Helsinki, Finland) was a Finnish missionary who worked for a long time in Ovamboland, Namibia. She held a master’s degree in the English language from the University of Helsinki, and she was known as the long time English teacher of the Oshigambo High School, which she co-founded together with Toivo Tirronen in 1960. Lehtonen was born on 3 August 1927, in Helsinki, to Reverend Mauri Lehtonen and his wife Margit Lehtonen. The family moved quite often, and Lahja Lehtonen went to primary school in Jämsänkoski. Later the family settled in the Messukylä parish in Tampere. Lehtonen studied languages at Helsinki University, following in the footsteps of her mother. Lehtonen’s first term as a missionary in Ovamboland took place in 1954–58, and right from the start she worked at Oshigambo, teaching in the girls’ school. After the Oshigambo High School had been founded, she taught there, and when Tirronen left for Finland in the mid-1970s, she took on the responsibilities of the principal. In 1977, her former student Timoteus Ndakunda became her vice principal. In 1980, they switched roles, and thereafter Lehtonen worked as the vice principal. In addition to working as a teacher, Lehtonen also wrote, together with Kirsti Ihamäki, a history book for Standard Three. When the South African Defence Forces established a base only from the school, Lehtonen protested strongly, and the base was moved to a new location from the school. When Namibia gained its independence, Lehtonen was eligible to vote, and she was given the honour of casting the first vote at the Oshigambo polling station. Lehtonen returned to Finland in 1991. In total, she worked in Ovamboland for more than 35 years. Lehtonen wrote the histories of the school system in Ovamboland and of the Oshigambo High School, and she translated the biography of Martti Rautanen that had been written by Matti Peltola in 1994. The translation appeared in 2002. In 1996, she published an English-Ndonga Dictionary, which she prepared in collaboration with Eljas Suikkanen, basing the work on the Ndonga-English Dictionary of Toivo Tirronen. Lehtonen also wrote a history of Oshigambo, 1650 to 1950, in Oshindonga. After her retirement, Lehtonen became concerned about the fate of the Ovambo language, which was losing ground to the English language, and she strongly advocated the use of Oshiwambo. The Ovambos gave Lehtonen the nickname Kanyeku.