diff --git a/build/docker/Dockerfile b/build/docker/Dockerfile
index 5e061fcc95..4f20c4109b 100644
--- a/build/docker/Dockerfile
+++ b/build/docker/Dockerfile
@@ -1,4 +1,5 @@
-FROM mcr.microsoft.com/dotnet/sdk:8.0.204-cbl-mariner2.0 AS build
+# --platform tells docker to always use the host platform for the build not the target platform. Runtime container will use target platform.
+FROM --platform=$BUILDPLATFORM mcr.microsoft.com/dotnet/sdk:8.0.204-cbl-mariner2.0 AS build
 ARG FHIR_VERSION
 ARG ASSEMBLY_VER
 
@@ -67,8 +68,9 @@ RUN dotnet restore ./src/Microsoft.Health.Fhir.${FHIR_VERSION}.Web/Microsoft.Hea
 
 COPY . .
 
-RUN dotnet publish /repo/src/Microsoft.Health.Fhir.${FHIR_VERSION}.Web/Microsoft.Health.Fhir.${FHIR_VERSION}.Web.csproj -c Release -o "/build" --no-restore -p:AssemblyVersion="${ASSEMBLY_VER}" -p:FileVersion="${ASSEMBLY_VER}"  -p:Version="${ASSEMBLY_VER}" -f net8.0
+RUN dotnet publish /repo/src/Microsoft.Health.Fhir.${FHIR_VERSION}.Web/Microsoft.Health.Fhir.${FHIR_VERSION}.Web.csproj -c Release -o "/build" --no-restore -p:AssemblyVersion="${ASSEMBLY_VER}" -p:FileVersion="${ASSEMBLY_VER}"  -p:Version="${ASSEMBLY_VER}" -f net8.0 -a $TARGETARCH
 
+# Implicitly uses the target platform for the runtime image.
 FROM mcr.microsoft.com/dotnet/aspnet:8.0.4-cbl-mariner2.0 AS runtime
 
 ARG FHIR_VERSION