The research examined the historical background of the Moken ethnic group at Lao Na Nok Island from the past until the present (2011) and investigated the impact of development from the state and private sectors after the 2004 tsunami disaster on the identity change of the ethnic group. The study results revealed that there was a rhetorical discourse in attempting to manipulate the ethnic lifestyle. The state sector previously provided humanitarian assistance to the ethnic group and later established a policy to revive the ethnic lifestyle in order to unite the group. The private sector attempted to give justice to the group as “them” and labeled their identity as inferior and underdeveloped, which required assistance. This put the ethnic group in a low position in their power relationship with outsiders. After the tsunami disaster, the ethnic group had the right to accept or refuse this discourse. Their ethnic consciousness thus affected their identity change later on.