A court in Istanbul ruled that Perihan Magden's article amounted to "heavy criticism conveyed within the scope of freedom of expression" and did not constitute a crime.
Magden was among a string of writers and journalists to stand trial for expressing opinions, despite pressure from the EU to scrap repressive laws and improve freedoms.
She is the second person to be acquitted in recent months. In November, a court acquitted Internet journalist Rahmi Yildirim of charges of insulting the military, the AP reports.
In her column, published in the weekly Yeni Aktuel magazine in December, Magden defended conscientious objector Mehmet Tarhan who was sentenced to a record four-year term in a military prison for disobedience after he refused to wear his military uniform. She argued that Turkey needed to establish a civilian service as an alternative to compulsory military conscription.