Purpose: Children’s results on school-related achievements tests, such as aspects of math, reading and writing, have been shown to decline following a lengthy summer vacation. Few studies have investigated whether this also applies to vocabulary skills. The purpose of this study is to investigate how lexical organization and retrieval, assessed by a semantic verbal fluency (SVF) task, develops during a lengthy summer vacation versus formal schooling.Method: Sixty-eight children with mean age of 7.9 (ranging from 6.5 to 9.1), were assessed pre- and post-summer vacation and post-fall semester using two SVF categories (Animals and Clothes). The number of words produced in both categories gave the total score.Results: The result of the SVF tests decreased following summer vacation. The loss was recouped at the post-fall semester assessment, but no gains compared to initial testing were shown. Neither level of parental education, general language ability, non-verbal IQ, nor bilingualism explained the variance in development during the summer vacation or the fall semester.Conclusions: Our findings indicate that a lengthy summer vacation causes a recess in the expected development of SVF ability and that this recess is recouped after a semester of formal schooling. The findings are in line with previous research indicating that summer vacation may have negative impact on the development of important scholastic abilities in children.