Many marine and terrestrial organisms lay down regular growth bands. In some species (e.g., trees), control of growth band geometry is related to environmental conditions. Coralline algae are long-lived marine plants with a global distribution that lay down regular calcitic growth bands composed of more- and less-extensively calcified cells. Little is known about environmental and organism controls on their growth. In this investigation, coralline algae (Lithothamnion glaciale Kjellm.) were grown at 8, 11, and 15°C, and temperature controls on algal growth were considered. Calcite density within less-extensively calcified cells in L. glaciale was negatively correlated to summer temperature. No relationships were observed between temperature and calcite density in more-extensively calcified cells or growth-band width itself. Additionally, temperature controls on growth in three L. glaciale thalli over the last 50 years were considered. Temperature was negatively related to calcite density in more- and less-extensively calcified cells but showed no consistent relationship with band width.