The thermal expansion characteristics of some glasses and glass-ceramics within the system LiAlSi 2 O 6 BaAl 2 Si 2 O 8 are described. The expansion coefficient of glass decreases with the increase of BaAl 2 Si 2 O 8 content, while both the transformation (T g ) and softening (T s ) temperatures increased. The thermal expansion coefficients of glass-ceramics exhibited a wide range depending upon the type and relative proportions of the crystalline phases present.The α-values of the studied glass ranged from 58.34 to 75.03×10 −7 /°C in the 20–300°C temperature range and those of the crystalline products ranged from 3 to 80×10 −7 /°C in the same temperature range. The break in the expansion curves of the crystalline samples at about 300°C defined the reversible transformation temperature of the orthorhombic⇆hexagonal-celsian.