On a sliding scale of one (poorly integrated) to eight (well integrated), the report by the Berlin Institute for Population and Development shows that Turkish immigrants came last with a score of 2.4 despite being the second most numerous immigrant group in the country.
They finished bottom of the table behind immigrants from the former Yugoslavia and Africa (3.2), the Middle East (4.1), southern Europe (4.4) and the Far East (4.6).
The most integrated group in Germany, according to the Berlin institute, is immigrants from other EU countries who score 5.5 on the institute's index.
The report's assessment is based on results from several criteria including education, assimilation into society and employment to make up its index.
Turks failing in education, assimilation and employment areas
In the area of education, the study shows that 30 percent of students of Turkish origin do not have a school leaving certificate and only 14 percent pass their final secondary school examinations. In the state of Saarland, 45 percent of Turkish immigrants have failed to complete their high school education.
In terms of assimilation into society, Turkish immigrants are marked down due to the fact that less than a third of Turks born in Germany have chosen to obtain German citizenship and 93 percent have married within the Turkish community.
Unemployment among Turkish immigrants is high and many survive on state benefits while the reports shows a large number of Turkish women remain in the home to manage the family.
In an article in the German news magazine Der Spiegel, Interior Minister Wolfgang Schaeuble defended the German government's initiatives to promote integration saying it was "on the right track" but added that more could be done.
"We must tell the socially weaker people, who have been isolated over generations: you are important," Schaeuble said. "We value you. You are as valuable as the others."
Some 15 million people in Germany are foreigners or of foreign origin, including just under three million Turks, representing just under 20 percent of the total population.
The largest group, statistically, are Germans repatriated from the former Soviet Union following its collapse and German reunification.