Physical inactivity has been one of the most critical threats to public health with obesity being one of the conditions associated with a physically inactive lifestyle (WHO, 2010). Scholars have indicated that obesity is one of the intractable consequences associated with a sedentary lifestyle increasing health risk factors, i.e., cardiovascular diseases, diabetes mellitus, and some cancers (Cairney et al., 2019; Ha et al., 2020). Physical literacy (PL) presents a holistic educational concept for promoting participation in life-long physical activity (Whitehead, 2010). The purpose of this dissertation, therefore, was to develop a PL instrument to measure the level of middle-school students' PL to provide information that might be needed to assist with planning to alleviate the negative effects of physical inactivity. This dissertation study used a cross-sectional survey design, and 328 middle-school students participated in the study. An exploratory factor analysis (EFA) was utilized to ascertain the underlying factor structure of the "Perceptions of Physical Literacy for Middle-School Students" (PPLMS) instrument. The findings of the EFA found a 22-item PPLMS instrument with four subscales: namely affectivity of physical activity, engagement in physical activity, perceived physical competence, and knowledge and understanding of physical activity. Subsequently, a confirmatory factor analysis (CFA) was used to confirm the EFA model, and the findings indicated an acceptable model fit (X[superscript 2]/df =1.487, RMSEA = 0.067, 90% CI [0.051, 0.083], SRMR = 0.062, TLI = 0.903, CFI =0.914). Moreover, findings of the Cronbach's alpha illustrated good internal consistency reliability measures for each subscale and the 22- item PPLMS instrument. The theoretically based 22-item PPLMS instrument is a reliable and valid instrument for measuring the level of PL for middle-school students in the southeastern United States. In addition, the 22-item PPLMS instrument may be practical as it offers sufficient information for educators or educational leaders to consider as they adapt their physical education curriculum in accordance with the theory of PL as part of promoting a healthy lifestyle for their students. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]