Surfactant‐assisted hydrothermal synthesis of magnesium‐doped hydroxyapatite (Ca10−xMgx(PO4)6(OH)2) with 0 ≤ x ≤ 1) was realized in aqueous solution at 90°C. β‐TCP phase was formed in the Mg0.6‐HA sample after heat treatment at 1000°C. Magnesium was found to degrade the sintering ability of Mgx‐HA ceramics. Flexural strength (σf) was found to decrease as a function of Mg‐doped HA. The using of carbon nanotubes as reinforcing agents mitigated the strength loss of Mg‐HA ceramics. The flexural strength of Mg0.6‐HA was then increased by nearly 20% from approximately 33 to 39 MPa with an optimum addition of 3 wt% of multi‐walled nanotubes.