diff --git a/src/Operations.jl b/src/Operations.jl
index c2ac100e5b..4777d10e91 100644
--- a/src/Operations.jl
+++ b/src/Operations.jl
@@ -2060,19 +2060,21 @@ function test(ctx::Context, pkgs::Vector{PackageSpec};
             test_fn !== nothing && test_fn()
             sandbox_ctx = Context(;io=ctx.io)
             status(sandbox_ctx.env, sandbox_ctx.registries; mode=PKGMODE_COMBINED, io=sandbox_ctx.io, ignore_indent = false, show_usagetips = false)
-            flags = gen_subprocess_flags(source_path; coverage,julia_args)
+            precompile_julia_args = Cmd(filter(!startswith("--threads"), julia_args.exec)) # precompilation with threads is not supported
+            precompile_flags = gen_subprocess_flags(source_path; coverage, julia_args = precompile_julia_args)
 
             if should_autoprecompile()
-                cacheflags = Base.CacheFlags(parse(UInt8, read(`$(Base.julia_cmd()) $(flags) --eval 'show(ccall(:jl_cache_flags, UInt8, ()))'`, String)))
+                cacheflags = Base.CacheFlags(parse(UInt8, read(`$(Base.julia_cmd()) $(precompile_flags) --eval 'show(ccall(:jl_cache_flags, UInt8, ()))'`, String)))
                 Pkg.activate(sandbox_ctx.env.project_file; #=io=devnull=#) do
-                    Pkg.precompile(sandbox_ctx; io=sandbox_ctx.io, configs = flags => cacheflags)
+                    Pkg.precompile(sandbox_ctx; io=sandbox_ctx.io, configs = precompile_flags => cacheflags)
                 end
             end
 
             printpkgstyle(ctx.io, :Testing, "Running tests...")
             flush(ctx.io)
             code = gen_test_code(source_path; test_args)
-            cmd = `$(Base.julia_cmd()) $(flags) --threads=$(get_threads_spec()) --eval $code`
+            flags = gen_subprocess_flags(source_path; coverage, julia_args = julia_args)
+            cmd = `$(Base.julia_cmd()) --threads=$(get_threads_spec()) $(flags) --eval $code`
             p, interrupted = subprocess_handler(cmd, ctx, sandbox_ctx, "Tests interrupted. Exiting the test process")
             if success(p)
                 printpkgstyle(ctx.io, :Testing, pkg.name * " tests passed ")