Acknowledgements section of master's thesis
You might want to peek at a few other examples to make sure there's no institutional norms, but you can often acknowledge whoever you want, and indeed its a good place to acknowledge more personal contributions.

For example, in mine I acknowledge:


My advisor
The other members of my committee
Some colleagues who provided data
A family member who used to be a member of a profession who I asked a few questions about
Several fellow students
My funding sources
StackOverflow and CrossValidated
My favorite purveyor of caffeine.