Growth of Pteria penguin pearl oysters was monitored for 20 mo, from April 2009 to November 2010, to investigate differences in growth performance at three dissimilar sites: Pioneer Bay, Cape Ferguson, and Horseshoe Bay in the Great Barrier Reef lagoon. Growth parameters generated with the von Bertalanffy growth function ranged from K = 0.09–0.32 and L_∞ = 283.6–822.5. Overall growth performance (Φ′) ranged from 4.40–4.77. Time to reach commercial size (T₁₀₀) was between 1.38 y and 1.54 y, and T₁₂₀ was between 1.74 and 1.92 y. A more accurate estimate of the L_∞ = 213.4-mm dorsoventral measurement (DVM) was obtained at Pioneer Bay by using a larger data set that incorporated a wider size range of oysters. Overall monthly increase in DVM of oysters held at Horseshoe Bay (5.3 ± 0.2 mm) was more than that at Pioneer Bay (4.7 ± 0.2 mm) and Cape Ferguson (4.9 ± 0.2 mm), and there were significant differences in the monthly DVM increase among the sites during growth measurement periods (P < 0.05). Monthly DVM growth was fastest (7.2 ± 0.2 mm) in small oysters (DVM, 50–70 mm) in the spring and summer and was lowest (2.4 ± 0.4 mm) in larger oysters (DVM, 105–110 mm) during the spring. Regression analysis showed anteroposterior measurement (APM), shell thickness (ST), and whole weight (WW) were significantly correlated with DVM for all groups (P < 0.001). In the commercial size class of 100–120 mm DVM, mean WW of oysters at Cape Ferguson was significantly greater (P < 0.01), and the APM-to-DVM ratio was also significantly greater for oysters at Cape Ferguson and Horseshoe Bay (P < 0.01), whereas there were no significant differences among groups with regard to the ST-to-DVM ratio. At all 3 sites, the highest mortalities (measured as a percentage) were recorded for small oysters (DVM, 25–50 mm) during the winter period. Suspended particulate inorganic matter (measured in grams) levels were significantly different among sites (P < 0.001). Comparison among growth rates obtained during this study demonstrate that there is significant variability in growth between sites in the Great Barrier Reef lagoon, and that P. penguin are able to tolerate—and even thrive-under a wide range of turbidity levels.