Attitudes of parents of typically developing children (TDC) towards school inclusion have been neglected by researchers, although their importance is unquestionable. This study characterizes the attitudes of Portuguese parents of TDC towards school inclusion of a child with some type of disability (Hearing Impairment, Down Syndrome and Behavior Disorder). The research also analyzes the impact in parental attitudes of the type of disability and of the neutral or positive description of the child with a disability. The associations between parental attitudes, optimism and the Big Five personality dimensions are also examined. A sample of 360 fathers and mothers of TDC, who attended elementary school, was collected. Parental attitudes were assessed through the survey Children with difficulties at school (Nota, Soresi, & Ginevra, 2015). Another two instruments were also used: the Life Orientation Test-Revised (LOT-R-Scheier, Carver, & Bridges, 1994) and the NEO Five Factor Inventory (NEO-FFI; Costa & McCrae, 1992). The results revealed that Portuguese parents tended to demonstrate neutral attitudes towards the inclusion of children with some kind of disability, and that they didn't considered that the presence of a child with a disability could be perceived as a resource or benefit by the school context. Regarding the effect of the variables analyzed, it was found that the type of disability and the type of description of the child with a disability significantly influenced parental attitudes: attitudes were more positive towards children with Hearing Impairment than towards children with Down Syndrome or Behavior Disorder; parental attitudes were also more positive when the child with a disability was described in a way that stressed his/her abilities. Small but statistically significant associations were also found between optimism and personality dimensions (agreeableness; conscientiousness) on one hand and parental attitudes, on the other hand. The implications of the results are discussed.