<p>This study explores light colors’ positive and negative effects on children with Autism Spectrum Condition (ASC). This study was conducted under the hard situation of COVID-19. It also demonstrated the possibility of research in unfamiliar and limited situations. Design and environment have a significant effect on ASC. Color, light, and spatial design aspects have been specifically studied before. However, to our knowledge, the color of light’s impact on children who are diagnosed with ASC has not been investigated in the literature. This study aims to fill the gap by asking two main research questions: Do participants’ behavior change significantly depending on the chosen colors of light? Which colors of light trigger positive and negative behaviors? Empirical research was conducted to answer the research questions. Six colors of light (blue, green, pink, yellow, red, and white light) and six typical behaviors (Playfulness, eye contact, refusal of task, repetitive body movement, repetitive speech, and aggression) were selected. The experiment relied on the observation of participants under different color settings of light. Thirteen children with low to mild levels of ASD, aged between five to eleven participated in this research voluntarily. The findings showed a relationship between the color of light and the behavior of children on the spectrum. It was found that playfulness was observed the most in yellow (84.6%), refusal of the task was most observed in white (38.5%), and eye contact was most observed in yellow (7.7%). Repetitive body movement was most observed in yellow (7.7%) and red light (7.7%). The repetitive speech was the most in red (7.7%) and blue (7.7%) light.</p>