Background: The study aimed to explore to what extent variables associated with lexical and sublexical spelling processes predicted single word spelling ability and whether patterns of lexical and sublexical processes were different across ages. Methods: Beginning (mean age 7 years, N=144) and advanced (mean age 9 years, N=114) English-speaking spellers completed tasks associated with sublexical processing (phonological ability and phonological short-term memory), lexical processing (visual short-term memory and visual attention span) and factors known to predict spelling (e.g., rapid automatised naming). Results: Phonological ability, rapid automatised naming, visual short-term memory and visual attention span were significant predictors of spelling accuracy for beginning spellers, while for more advanced spellers, only visual attention span was a significant predictor. Conclusions: The findings suggested that for beginning spellers, both lexical and sublexical processes are important for single word spelling, but with increasing literacy experience, lexically related variables are more important.