Ms Alderson (26) specialises in oceanic prehistory.
The lucrative Gates Cambridge Scholarship will enable her to pursue doctoral studies at Cambridge later this year.
University of Otago officials said she won the scholarship after being chosen as one of 54 international scholars selected from a total pool of 3535 applicants.
The Gates Cambridge Scholarships were established by the Bill and Melinda Gates Foundation in 2000 with a $US210 million endowment, to enable outstanding graduate students from outside the United Kingdom to study at Cambridge University.
These applicants were assessed on their intellectual ability, leadership capacity, academic fit with Cambridge and their commitment to improving the lives of others.
The value of Ms Alderson's scholarship amounted to about $NZ73,570 per year, and also included airfares, visa costs and other benefits.
She was ''delighted and honoured'' to have been offered a Gates Cambridge Scholarship, and this support would help her promote, on a larger scale, the discipline of archaeology within Micronesia, which was ''the most understudied region in the Pacific'', Ms Alderson said.
She initially studied at Victoria University of Wellington before moving to Otago in 2010 to complete her honours year and undertake a master's degree in anthropology and archaeology.
Born in Auckland, she grew up in Nelson, attending Nelson College for Girls.
Her time at Cambridge begins on October 1, and the scholarship covers three years of study.
Otago University was a world leader in archaeology in the Pacific, and she owed her interest in that region to the archaeology team in the Otago anthropology and archaeology department.
And she had been inspired by the chance to study ''the incredible things right on our doorstep'', she said.
The research coming out of Otago University had ''really inspired'' her to move from an interest in Greece and Rome to realise ''how much exciting archaeology is right on our doorstep in New Zealand, and the broader Pacific''.
She has worked in Vanuatu and Hawaii, and most recently as a consultant archaeologist in Christchurch.