Finland is known for its high-performing educational system, but local assessments have shown that performance has declined during the past decade. We report the results of nationally representative learning to learn assessments in which 15-year-olds took an identical test in the same schools in 2001, 2012 and 2017. The results show that the level of both domain-general cognitive performance and learning-related beliefs dropped dramatically from 2001 to 2012, but the negative trend has stopped since then. For learning-related beliefs, the 2017 results were approaching the 2001 baseline level. The findings indicate that we may not be dealing with a true anti-Flynn effect, but the decline can possibly be explained by reduced motivation and effort in low-stakes assessment and schoolwork.