Theories of reading and writing development suggest that the factor structure of achievement batteries could change across development. As a result, it is important to test achievement batteries for invariance across development. The purpose of these analyses is to determine whether the factor structure of reading, writing, and oral language measures is invariant across grade ranges in the Kaufman Test of Educational Achievement, 3rd Edition. Results suggest that multiple interpretational models demonstrate measurement and structural invariance. Implications for practice are discussed.