Cross-linguistic skills transfer from the first language (L1) to the second/foreign language (L2) has been widely investigated and the impact of L1 on L2 learning has been documented. On the other hand, there are few studies that have investigated the reverse transfer of skills that are from L2 to L1. These studies support the CRT hypothesis which claims that such a transfer exists and that when an intervention program for the improvement of specific linguistic skills in L2 is applied in children with learning disabilities there is an improvement of the same skills in their L1, except for spelling skills (Abu-Rabia & Bluestein-Danon, 2012; Abu-Rabia, Shakkour, & Siegel, 2013). In the present study, a linguistic skill transfer from L2 (English) to L1 (Greek) is investigated, after an intervention in the L2, among secondary school students with learning disabilities (LD). The students (mean age 13.6 years old) were divided into an experimental group which received an intervention in L2's decoding and spelling skills and also into a control group which did not receive any intervention. Both groups were tested in their decoding reading skills and spelling in both languages. Our results showed that there was a transfer from L2 to L1 for decoding skills in the intervention group but not for spelling. These findings are in line with the CRT Hypothesis giving support to a linguistic skill transfer from L2 to L1, except for orthographic knowledge which seems to be language specific.