General practitioners (GPs) could have an important role in early diagnosis of autism. There have been no studies evaluating the knowledge of GPs regarding autism in Pakistan. We aimed to fill that gap by assessing knowledge and attitude of GPs in Karachi regarding autism. We conducted a cross-sectional survey of 348 GPs; only 148 (44.6%) had heard of “autism.” Our results show that GPs less than 30 years of age and those who obtained their Medical Degree in the last 5 years are more likely to report knowledge about autism: OR = 3.0; 95% CI: 1.71, 5.31, and OR = 2.56; 95% CI: 1.48, 4.42, respectively. In addition, among those reporting knowledge about autism, many held misconceptions regarding the signs and symptoms and etiology.