This study examined the contribution of attachment security and emotion regulation (ER) to the explanation of social information processing (SIP) in middle childhood boys with learning disabilities (LD) and without LD matched on age and grade level. Children analyzed four social vignettes using Dodge's SIP model and completed the Kerns security scale and the children's self-control scale. Study results demonstrated major difficulties in SIP, lower attachment security, and less ER in children with LD compared to children without LD. Attachment as well as the interaction between attachment and ER emerged as important contributors to most SIP steps, suggesting that children with higher security who also have better ER skills will have better SIP capabilities along the different steps, beyond group inclusion. Results were discussed in terms of practical and clinical implications regarding the importance of mother-child attachment and ER skills for social cognitive capabilities in children with LD. (Contains 3 tables.)