A novel flattened bamboo-wood composite cross-laminated timber (CCLT) made from flattened bamboo and hemlock lumber was developed, and its mechanical performance was investigated and quantified in this work. The results demonstrated that the CCLT columns and control hemlock CLT counterparts had nearly equal axial compression strength, but the CCLT yielded a higher compression modulus of elasticity (MOE). Additionally, the CCLT compression behaviors were not significantly affected by the height. Compared with hemlock CLT, the CCLT exhibited a slightly higher flatwise bending MOE and strength in the major strength direction. Furthermore, the MOE and strength of the CCLT under edgewise bending were 17.3% less and 16.2% greater than those under flatwise bending, respectively. The load-carrying capacity of the CCLT was mainly governed by the interfacial failure between the bamboo and wood, in which no rolling shear failure was observed. Those features are unique for the new CCLT for engineered applications.