Although up to 8% of European youngsters carry out high-intensity care for a family member, adolescent young carers (AYCs), especially those caring for their grandparents (GrPs), remain an under-researched group. This study aimed at addressing the current knowledge gap by carrying out an online survey in Italy, the Netherlands, Slovenia, Sweden, Switzerland, and the United Kingdom. The analysis included a final sample of 817 AYCs aged 15–17 years old. AYCs of grandparents (GrPs) were compared to AYCs of other care recipients (OCRs), in order to identify any difference in positive and negative caregiving outcomes and exposure factors between the two groups. Linear or logistic regression models were built, and multivariate analyses were repeated, including a fixed effect on the country variable. AYCs of GrPs experienced more positive caregiving outcomes than AYCs of OCRs across all six countries. Being female or non-binary, and having a migration background, were associated with more negative outcomes, regardless of the relationship with the care recipient. Further research on intergenerational caregiving outcomes is recommended for shaping measures and policies, which preserve the intergenerational emotional bonds, whilst protecting AYCs from inappropriate responsibilities, undermining their mental health and well-being.