The advancement of technology has affected human behavior. Social media has become a prominent platform for our lives to share opinion, thoughts, and information. Those activities are stored as a digital trace. Meanwhile in linguistic approach, the unique way of people writing is able to reveal the real personality. The open access data on social media give us an opportunity to assess the characteristic of a person based on a digital trace. The human personality has been classified according to Five Factor Model (FFM). We propose the ontology modeling approach to measure human personality using social media data, particularly in Bahasa Indonesia. The present personality measurement commonly use a test or questionnaire survey. This research enriches current methodology to measure human personality by observing writing and linguistic usage on Twitter. The result is beneficial for marketing study to forecast consumer behavior. It also valuable fo human resources study to decide employee's recruitment and promotion. © 2018 IEEE.