The purpose of the present study was to determine the perception of schoolchildren whether their academic performance improved or worsened during the pandemic, analyzing their social anxiety, gender, use of masks in the classroom, and school year. The total sample was 107 primary school students (25 in the fourth, 40 in the fifth and 42 in the sixth grade), with a mean age of 10.51 years old (SD = 1). The gender were 58 girls and 49 boys, from a school in the province of La Coruña (Spain). The study was based on a quantitative methodology, and the design was cross-sectional, descriptive, observational and correlational. The social anxiety questionnaire (CASO-N24) was used to assess social anxiety, and an ad hoc self-report register was elaborated to evaluate sociodemographic variables. The results indicated that 44.8% of the schoolchildren considered that the pandemic had neither improved nor worsened their academic performance. Although 38.3% considered that high and very high social anxiety increased progressively as the school year progressed, both in boys and girls. Besides, the schoolchildren who presented very low and low social anxiety improved their grades in Physical Education, while those who presented high social anxiety worsened them. In conclusion, having a low social anxiety, lower grades before the pandemic and higher grades after, makes children perceive an improvement in their academic performance during the pandemic.