Background: Although physical literacy is explicitly defined and integrated into Canadian provincial physical education curricula, limited empirical evidence substantiates the development of physical literacy in elementary physical education. Despite physical education curricular expectations, developing and assessing physical literacy in students may be difficult for teachers with little to no background in physical literacy or physical education. Purpose: The primary purpose was to explore the effect of a curricularly linked physical literacy enriched intervention in elementary school physical education. A secondary purpose involved an examination of the intervention's effects on sex differences. Design: A quasi-experimental controlled intervention trial with a matched comparison group was used to determine the impact of a curricular-based physical literacy enriched physical education intervention on students' development of physical literacy. Teachers (n = 6) and students (n = 131) from four Saskatchewan elementary schools participated in either a PLitPE (experimental) condition or a usual practice (control) condition. The PLitPE intervention was created using learning principles consistent with physical literacy and Self-Determination Theory. PLitPE instructional elements were developed with input from thirteen teachers who were members of the local school division's physical education professional learning community. An embedded professional development model was used where a mentor teacher was present to facilitate and support the implementation of the PLitPE intervention. The Physical Literacy Assessment for Youth tools were used to assess motor competence (PLAYfun), student self-description (PLAYself), and movement participation (PLAYinventory). Each domain of physical literacy (physical competence, psychological, and behavioural) was evaluated using these tools. Results: Significant differences, favouring PLitPE over control, were observed for average motor competence (M = 49.4, M = 40.0, p < 0.001, PLAYfun), movement vocabulary (M = 10.3, M = 7.5, p < 0.001, PLAYfun), environmental participation (M = 423.9, M = 390.1, p < 0.05, PLAYself), and a reduction of sex differences on average motor competence and movement vocabulary. Statistically significant relationships with low to fair correlations between PLAYfun and PLAYself variables existed. Conclusions: This study provides empirical evidence supporting physical literacy enriched physical education. PLitPE developed the psychological domain (affective and cognitive) and significantly improved physical competence, however, the intervention did not manifest in improved behaviour. Concerning sex differences, the intervention yielded an equal and substantive improvement in both males and females in the intervention group. Future studies should consider the addition of reflective approaches, as well as the construction of positive challenges for children.