5G networks are gaining pace in development and deployment in recent years. One of 5G’s key objective is to support a variety of use cases with different Service Level Objectives (SLOs). Slicing is a key part of 5G that allows operators to provide a tailored set of resources to different use cases in order to meet their SLOs. Existing works focus on slicing in the frontend or the C-RAN. However, slicing is missing in the fronthaul network that connects the frontend to the C-RAN. This leads to over-provisioning in the fronthaul and the C-RAN, and also limits the scalability of the network. In this paper, we design and implement Fronthaul Slicing Ar- chitecture (FSA), which to the best of our knowledge, is the first slicing architecture for the fronthaul network. FSA runs in the switch dataplane and uses information from the wireless sched- ule to identify the slice of a fronthaul data packet at line-rate. It enables multipoint-to-multipoint routing as well as packet prior- itization to provide multiplexing gains in the fronthaul and the C-RAN, making the system more scalable. Our testbed evaluation using scaled-up LTE traces shows that FSA can support accurate multipoint-to-multipoint routing for 80 Gbps of fronthaul traffic. Further, the slice-aware packet scheduling enabled by FSA’s packet prioritization reduces the 95th percentile Flowlet Completion Times (FCT) of latency-sensitive traffic by up to 4 times.