Boneless, skinless chicken thighs take five to seven minutes per side to cook on a grill. They should be grilled over medium to high flames with the lid closed to retain heat. The meat is done when the juices run clear after being pierced with a fork or a knife.
Brushing the grill with oil prior to adding the chicken helps conduct heat and ensures quick, even cooking, as does cooking on a preheated grill. This also helps ensure that the chicken does not stick to the grill and burn. The cook should add barbecue sauce or marinade, if desired, shortly before taking the meat off the grill to prevent the sugary sauce from burning.