The surname "Oka" is of Japanese origin and can be found in various regions of Japan. It is often associated with families that have historical ties to specific areas or professions. In Japan, surnames typically reflect geographical features, occupations, or characteristics of the family. In addition to its Japanese roots, "Oka" can also be found in other cultures, including as a surname in some Slavic countries. The name may have different meanings and origins depending on the cultural context, but it remains a relatively uncommon surname globally.