This paper explored al-Farabi’s and Thomas Aquinas’ ideas on politics, especially on the form of government. Medieval centuries remarked new formulations of political philosophy which was different from its Greek predecessors. Although almost impossible to totally detach from ancient Greek political ideas, medieval philosophers had attempted to adapt, renew and reformulate Greek political philosophy so as to fit with their circumstances. Al-Farabi and Thomas Aquinas were among attractive and influential philosophers who undertook this task of the reformulation of political ideas. Among new things inserted into ancient political philosophy by al-Farabi and Aquinas were political ideas of their religious teachings and the needs of their contemporary political situation. Referring to their writing on politics, both al-Farabi and Aquinas seemed to favor monarchy or a single supreme ruler as the best regime. However, a close investigation on their political ideas opened other possibilities of the forms of government when the situation of such ideal regime did not apply.