diff --git a/src/xla/Client.jl b/src/xla/Client.jl
index ccf715c1ba..3d0e3dd117 100644
--- a/src/xla/Client.jl
+++ b/src/xla/Client.jl
@@ -13,4 +13,14 @@ function get_device end
 function get_addressable_device end
 function platform_name end
 
-default_device(client::AbstractClient) = first(addressable_devices(client))
+"""
+    DEFAULT_DEVICE :: Ref{Int}
+
+0-based index of default device to use.
+By default, the value of the environment variable `REACTANT_DEFAULT_DEVICE` is used when set to a non-negative integer, otherwise it is set to 0 (first available device).
+"""
+const DEFAULT_DEVICE = Ref{Int}(0)
+
+function default_device(client::AbstractClient)
+    return addressable_devices(client)[DEFAULT_DEVICE[] + 1]
+end
diff --git a/src/xla/XLA.jl b/src/xla/XLA.jl
index 5fa34457b1..31335f2803 100644
--- a/src/xla/XLA.jl
+++ b/src/xla/XLA.jl
@@ -158,6 +158,13 @@ function __init__()
                 1
         end
 
+        if haskey(ENV, "REACTANT_DEFAULT_DEVICE")
+            DEFAULT_DEVICE[] = max(
+                0, something(tryparse(Int, ENV["REACTANT_DEFAULT_DEVICE"]), 0)
+            )
+            @debug "REACTANT_DEFAULT_DEVICE: " DEFAULT_DEVICE[] maxlog = 1
+        end
+
         @debug "REACTANT_XLA_RUNTIME: " REACTANT_XLA_RUNTIME maxlog = 1
 
         @ccall MLIR.API.mlir_c.RegisterEnzymeXLACPUHandler()::Cvoid