In this study, we present a new diagnostic test for dyslexia, called the Flamingo Test, inspired by the French Alouette Test. The purpose of the test is to measure students' word decoding skills and reading fluency by means of a grammatically correct but meaningless text. Two experiments were run to test the predictive validity of the Flamingo Test. In the first experiment, we compared reading times, error rates and, sensitivity and specificity of the Flamingo Test for samples of students with and without dyslexia. In the second experiment, we compared performance on the Flamingo Test with reading performance on two Dutch standard word reading tests: the Leestest Een Minuut voor Studenten (LEMs; 'one-minute word reading test for students') and the Klepel, a one-minute pseudo-word reading test. Again, students with dyslexia and matched non-dyslexic students were included. Our results show that sensitivity and specificity, as well as the positive predictive value (PPV), of the Flamingo Test are high, with even slightly higher PPVs for the Flamingo Test than for LEMs and Klepel. Together with the fact that the test is short and easy to administer, we believe that the Flamingo Test is a valuable new diagnostic instrument to assess reading skills.