Single-storey load-bearing masonry walls are widely used in warehouses, gymnasiums, and retail stores. North American design standards define load-bearing walls with a height-to-thickness greater than 30 as slender. Research is limited due to the cost and time required to test representative specimens. The way we build slender masonry walls has stayed essentially the same for decades, and standards have set requirements that are often too conservative due to the lack of data. A new research program at the University of Alberta assesses new techniques to improve the out-of-plane response of slender masonry walls. An 8.75 m tall partially-grouted concrete masonry wall with an alternative reinforcement arrangement was built, placing vertical bars at the edge of the grouted cells to increase their flexural contribution. The wall was subject to combined vertical and out-of-plane loads. The wall response is presented along a comparison with a typical masonry wall with bars centrally placed. The tested wall reached three times the capacity of a typical wall. It also exhibited reduced displacements in all stages of loading compared to the typical wall, with a reduction of 25% at ultimate. Results suggest that placing the bars farther from the out-of-plane neutral axis effectively increases the strength and stiffness of slender masonry walls. The new wall had a sudden failure mode after bars yielded, with visible damage in a lap-splice region. A numerical model in OpenSEES was validated with the test results.