<p>Elementary science teachers participated in a two-year professional development workshop to learn how to use epistemic tools in science classrooms for meaningful learning. The teachers’ epistemic orientation was examined on four occasions with a short form of the Epistemic Orientation Survey (EOS-SF). Results from complete data (<i>N</i> = 148) with the curve-of-factors model (CFM) showed that measurement invariance was obtained for the first-order factors indicating that the EOS-SF measured the teachers’ epistemic orientation across time. Furthermore, the growth model of the second-order factors was achieved suggesting that elementary science teachers’ epistemic orientation grew over time. The growth pattern showed that teachers’ epistemic orientation changed faster in the first six months of the professional development (PD) program than in the following year and a half. The finding of growth in teachers’ epistemic orientation may imply that the workshops for elementary teachers to learn epistemic tools contributed to a shift in teachers’ epistemic orientation.</p>