Numerous studies have shown that parents of children with Autism Spectrum Disorder(ASD) experience elevated levels of stress (Khawar & Saeed, 2016; Padden & James, 2017; Pisula & Porebowicz-Doersmann, 2017; Tripathi, 2015). Therefore, current study focused the perceived stress among parents of children with ASD. Present study conducted in two phases. Phase-I aimed to develop an indigenous Parental Perceived Stress Scale(PPSS) in Urdu language for parents of children with ASD. It was also aimed to determine the psychometric properties of PPSS. For scale development, an item pool of 46 items was generated based on the Lazarus and Folkman Stress Model (Lazarus & Folkman, 1984) and interviewing the parents having children with ASD. Generated items were evaluated by a panel of experts and were pilot tested on 25 parents. For Field study, a purposive sampling technique was used to select the sample of 502 parents of children with ASD from different special educational institutes.Multiple analyses of correlation, exploratory factor analysis, confirmatory factor analysis and reliability analyses were used. Exploratory factor analysis fixed to seven factor structure with 42 items. Confirmatory factor analysis was used to confirm the structure retained through EFA.Model indicated a good model fit with (chi-square=977.13, df=439, CFI=0.901, RMSEA=.070, GFI=0.81). Scale has Cronbach alpha of 0.95. It has good test-retest reliability (r=.79**, p<.01). Newly developed scale also showed good convergent and divergent validity. Phase-II aimed to examine the effects of stress management program on perceived stress of mothers having children with ASD. Additionally, Quality of life and depressive symptoms of mothers were also compared at pre and post-treatment levels. It further, explored the maternal qualitative perspectives about understanding of stress and ASD at pre-treatment level and evaluation of stress management program at post-treatment level. Sample of 55 mothers having children with ASD was selected through purposive sampling technique. Perceived Stress was measured by using Parental Perceived Stress Scale before and after stress management program. Stress management program provided in 10 group sessions of 90 minutes each. Twice a week group sessions were given to five groups of participants.Findings indicate a statistically significant difference in perceived stress at pre (M=136.80, SD=20.00) and post-treatment (M=75.52, SD=15.75, t=23.2, p>.001) levels. Similarly, statistically significant differences were found in quality of life (M=109, SD=9.27, M=66.03, SD=18.69, t=-17.08, p<.001, 95% CI) and depression (M=9.61, SD=5.67, M= 42.16, SD=10.3821.96, p<.01, 95%CI) of mothers at pre and post-treatment levels. Major themes and sub-themes emerged from qualitative data at pre-treatment levels were unawareness about the nature of ASD, uncertainty about child’s future, lack of effective coping strategies, social stigma, stressful effects on family quality of life and dire need of parental training. While, at post-treatment level, themes or sub-themes of stress reduction, learning of coping strategies and change in attitude towards children were emerged. Present study provides an indigenous reliable and valid instrument to measure the perceived stress of parents having children with ASD. Further, it indicates that stress management program reduces maternal stress, depression and improve their quality of life. Clinical implications of the study indicate the use of PPSS at clinical settings for identification of parental perceived stress. Further, it highlighted the need of awareness seminars and training workshops for parents of children with ASD.