The single crystal of CaBi₂B₂O₇ was obtained by recrystallization in solid-state and studied by single-crystal X-ray diffraction. Its crystal structure was refined in the centrosymmetric orthorhombic space group Pnma with a = 8.5556(8) Å, b = 5.1569(5) Å, c = 9.6677(7) Å, Z = 4. The structure is based upon parallel (0 1 0) {CaBi₂B₂O₇}_∞ layers from BO₃ triangles, ψ-tetrahedral BiO₃ groups, and CaO₆ triangular prisms connected each to other via long and weak Bi–O bonds. This borate is representative of MBi₂B₂O₇ family (M = Ca, Sr, Ba), where all members can be obtained from the hypothetical hexagonal aristotype. Thermal expansion is studied by high-temperature X-ray powder diffraction, its strongly anisotropic and negative along [0 0 1]: α_a = 11.8(1) × 10⁻⁶ °C⁻¹, α_b = 34.2(3) × 10⁻⁶ °C⁻¹, α_c = –25.7(4) × 10⁻⁶ °C⁻¹ at 600 °C. As a result, a/c cell parameters ratio tends to ideal √3 value, corresponding to the hexagonal aristotype.