In fall 2018, the Local Control Funding Formula Research Collaborative (LCFFRC) conducted surveys of stratified random samples of California superintendents and principals. Superintendent results were published in June 2018 in "Superintendents Speak: Implementing the Local Control Funding Formula." This report, "Principals' Perceptions: Implementing the Local Control Funding Formula," is the companion account of principal survey results. Highlights of this survey include: (1) A strong majority of principals (86%) agree the LCFF is leading to greater alignment among school goals, strategies, and resource allocation decisions; (2) A substantial majority of principals (72%) report the LCFF has increased their school budget flexibility; (3) A strong majority of principals (82%) agree the LCFF has enabled their school to improve services for low-income students, English learners, and foster youth; (4) Principals report their school has received guidance from their district on strategies to support student success, including ensuring students have access to fully credentialed teachers (82%), implementing state standards (75%), and improving school climate and safety (72%); (5) A substantial majority of principals (77%) report they have received guidance from their district to support two of the three LCFF target groups--low-income students and English learners--but guidance on supporting foster youth has lagged; and (6) Three-quarters of principals (75%) agree the LCFF is leading to improvement in student academic outcomes at their school. [This report was written with the assistance of Ashley Campbell, Kyra Capary, and Laura Tobben. For the companion report, "Superintendents Speak: Implementing the Local Control Funding Formula," see ED594774.]