This study examined differences in family characteristics, maternal knowledge about the educational program planning process, and maternal knowledge about children's individualized educational plans (IEPs) among families where parents never attended program planning meetings, inconsistently attended these meetings, or attended all of their children's IEP meetings. Nonattending families tended to have lower incomes and less parental education and included more single parent families and nonwhite families. Mothers from nonattending families placed more responsibility for their children's educational programs on professionals and had less information about the program planning process than mothers from other families. These mothers also knew less about their children's educational goals and objectives, the assessment data available on their children, and the support services received by their offspring. Mothers who attended program planning meetings believed that they benefited from attending, but many believed that their presence made no difference as to the outcome of the meeting. Suggestions for increasing parent involvement are presented.