Penelitian ini bertujuan untuk mengetahui faktor-faktor yang mempengaruhi Millennial attitude terhadap iklan Instagram di Indonesia, faktor yang dimaksud adalah credibility, irritation, informativeness, entertainment, personalization, dan menganalisa pengaruh Millennial’s attitude akan iklan Instagram terhadap purchase intention. Penelitian dilakukan pada pengguna Instagram di Indonesia dengan jumlah subjek penelitian sebanyak 197 pengguna yang termasuk dalam kriteria generasi Milenial dengan menggunakan Teknik convenience sampling. Data pada penelitian ini diperoleh menggunakan kuesioner dengan skala Likert yang terdiri dari 21 butir pernyataan, Analisis data dilakukan dengan menggunakan metode Partial Least Square. Berdasarkan hasil analisis data menunjukkan bahwa variabel Credibility, Informativeness, Entertainment, dan Personalization memiliki pengaruh positif dan signifikan terhadap Attitude towards Advertisement di Instagram. Sedangkan variabel Irritation tidak memiliki pengaruh terhadap Attitude towards Advertisement di Instagram. Penelitian ini juga menunjukkan bahwa Attitude towards Advertisement memiliki pengaruh dan signifikan terhadap purchase intention. / This study aims to determine the factors that influence Millennial’s attitude towards Instagram advertising in Indonesia, the factors are credibility, irritation, informativeness, entertainment, personalization, and this study is also analyze the influence of Millennial's attitude towards Instagram advertising on purchase intention. The study was conducted on Instagram users in Indonesia with a total of 197 users who were included in the Millennial generation criteria using convenience sampling technique. The data in this study were obtained using a questionnaire with a Likert scale consisting of 21 statement items. Data analysis was carried out using the Partial Least Square method. Based on the results of data analysis, it shows that the variables of Credibility, Informativeness, Entertainment, and Personalization have a positive and significant affect on Attitude towards Advertisement on Instagram. While the Irritation variable has no effect on Attitude towards Advertisement on Instagram. This study also shows that Attitude towards Advertisement significantly effect on purchase intention.