Respiratory sinus arrhythmia (RSA) represents the activity of the vagus nerve and is an indicator of parasympathetic activity. Low levels of RSA at rest indicate blunted parasympathetic activity. Porges’ Polyvagal Theory suggests that vagus nerve activity is linked to one’s ability to regulate their physiological states and social behaviors (Porges, 2007). Many studies have shown that there is a difference in RSA values between autistic and nonautistic individuals, which is thought to be connected to weakened stress responses and a decreased ability to adapt in social situations (Cheng, 2020). While these studies have shown that these two groups differ at rest, many of them lacked ecological validity as they were conducted in a laboratory setting. Thus, our research question aimed to answer if there are differences in RSA at baseline between autistic and non autistic adolescents in a more ecologically valid setting using data collected in participants' homes. Twenty-two (11 autistic, 11 nonautistic) youth,Mage 12.9 years (SD=0.85) participated in the current study. Participants were asked to wear a Zephyr Bioharness and biomodule that gathered physiological data including heart rate and breathing rate for around 10 minutes for 1-3 timepoints in a home setting. We then processed the data into RSA values. Using an independent sample t-test, we found that there were significant differences in RSA values between the two groups. Specifically, autistic adolescents were found to have lower RSA during at-home baselines relative to the nonautistic group (t=3.247, p= <0.01). Our study produced similar results as previous research, but in a more ecological setting.