During summer vacation, lower-achieving students experience learning loss in writing. This study investigated online summer tutoring for first grade writers. The four participants were six months to two years below grade level on at least two of written expression, spelling, and handwriting fluency. A multiple probe design with five phases was used: (1) Baseline; (2) transcription intervention; (3) mid-assessment; (4) Self-Regulated Strategy Development intervention (SRSD); and (5) post-assessment. The transcription phase increased handwriting fluency, spelling in text, and spelling of frequently misspelled words, but not handwriting legibility. The SRSD intervention produced large gains in word count, holistic text quality, and Test of Early Written Language-3 Contextual Writing. Online tutoring can prevent summer learning loss and improve written expression.