Background: Reading can be assessed using different materials, including non-words and texts. Unlike reading words or non-words, reading a text may be supported by reading comprehension, and the extent of this support could change with the amount of schooling. Aim: The present study aimed to examine how reading decoding in a shallow orthography like Italian changed with years of schooling, depending on the type of material and the contribution of non-word reading and reading comprehension to text reading speed. Methods: Six hundred and forty two typically developing Italian students from 8 to 16 years old were involved. They were administered grade-appropriate tasks assessing text reading speed, non-word reading speed, and reading comprehension. Results: The results showed that, although the two reading speed measures correlated closely, non-word reading speed improved only slightly with age, while the increase in text reading speed was steeper. Reading comprehension was a significant direct predictor of text reading speed after controlling for non-word reading speed. Importantly, however, while the difference in reading speed between non-words and text widened with schooling, the role of reading comprehension declined significantly, the [delta]R[superscript 2] dropping from 0.10 in primary school to just 0.01 in high school. Conclusions: These findings and their implications are discussed in the light of the relationship between reading comprehension and reading speed in a language with a shallow orthography across school grades.