The first Samoan to obtain a law degree in New Zealand, and the first to be admitted as a barrister and solicitor, Olive Nelson was the first woman to practise as a barrister and solicitor in Samoa.

Olive Nelson was born in Samoa.Her mother was Rosabel Moors and her father was Ta’isi Olaf Frederick Nelson, a successful businessman, scholar and leader of the Mau movement. New Zealand's colonial administrators banished him from Samoa to New Zealand for two periods during Olive's childhood and early adulthood and he spent over seven and a half years in New Zealand without any right of return to his home country. During the 1920s he gave valuable financial support for the Mau, which led a non-violent campaign for Samoan freedom and independence.

Brought up with her five sisters on the family estate at Tuaefu, Olive and her sisters were sent to New Zealand to attend school. Her mother remained in Samoa.

In 1931 Miss Nelson began studying law at Auckland University College. She was awarded the Butterworth Prize in 1931 for the highest marks in jurisprudence. She graduated LLB in April 1936 and was admitted as a barrister and solicitor of the Supreme Court of New Zealand in August 1936.

Olive Nelson returned to Samoa after graduating. She was back in New Zealand in 1938, accompanying her father and a delegation which attempted to meet New Zealand's Prime Minister. She was the delegation's legal adviser.

In 1942 she married Samoan politiial Gustav Frederick Betham. He later became the first Minister of Finance for Western Samoa when independence was won in 1962. They had two children, Barry and Leone. 

Olive Nelson died on 18 March 1970 aged 53.