Purpose: This study investigates whether FLINK, a newly developed digital reading training addressing silent reading fluency, is an effective way to increase the reading speed in an external standardized reading test (quop) of participating children. Method: 725 German-speaking third graders participated in FLINK as well as in the learning progress assessment platform quop, in which their reading speed was continuously monitored throughout the school year. A latent growth curve model was used to evaluate training gains with group (high vs. low training intensity) as predictor. Results: The analyses revealed a significant linear and quadratic growth of reading speed over the school year. The group with high training intensity showed a higher growth in the external reading speed test, confirming the effectiveness of the training approach regarding the improvement of reading speed. Conclusion: The digital reading fluency training FLINK, implemented in the learning progress assessment platform quop, can be considered as an effective way to foster reading speed in German-speaking children in third grade. Further analyses should focus on long-term and time-specific training effects simultaneously in order to obtain insights into the training’s mechanisms of action.