diff --git a/Make.inc b/Make.inc
index 216fc6fd7adde..b9d94d561ec91 100644
--- a/Make.inc
+++ b/Make.inc
@@ -80,8 +80,8 @@ HAVE_SSP := 0
 WITH_GC_VERIFY := 0
 WITH_GC_DEBUG_ENV := 0
 
-# Use stock if MMTK_PLAN hasn't been defined
-MMTK_PLAN ?= None
+# Use Immix by default
+MMTK_PLAN := Immix
 
 # Enable DTrace support
 WITH_DTRACE := 0
@@ -1402,7 +1402,7 @@ CSL_NEXT_GLIBCXX_VERSION=GLIBCXX_3\.4\.33|GLIBCXX_3\.5\.|GLIBCXX_4\.
 # Note: we explicitly _do not_ define `CSL` here, since it requires some more
 # advanced techniques to decide whether it should be installed from a BB source
 # or not.  See `deps/csl.mk` for more detail.
-BB_PROJECTS := BLASTRAMPOLINE OPENBLAS LLVM LIBSUITESPARSE OPENLIBM GMP OPENSSL LIBSSH2 NGHTTP2 MPFR CURL LIBGIT2 PCRE LIBUV LIBUNWIND DSFMT OBJCONV ZLIB P7ZIP LLD LIBTRACYCLIENT BOLT
+BB_PROJECTS := BLASTRAMPOLINE OPENBLAS LLVM LIBSUITESPARSE OPENLIBM GMP OPENSSL LIBSSH2 NGHTTP2 MPFR CURL LIBGIT2 PCRE LIBUV LIBUNWIND DSFMT OBJCONV ZLIB P7ZIP LLD LIBTRACYCLIENT BOLT MMTK_JULIA
 define SET_BB_DEFAULT
 # First, check to see if BB is disabled on a global setting
 ifeq ($$(USE_BINARYBUILDER),0)
@@ -1426,6 +1426,13 @@ $(error "Attempting to build OpenBLAS or SuiteSparse without a functioning fortr
 endif
 endif
 
+ifneq (${MMTK_PLAN},None)
+# We still need some .h files from mmtk when
+# building Julia using the BinaryBuilder
+ifeq ($(USE_BINARYBUILDER_MMTK_JULIA),1)
+MMTK_API_INC=$(JULIAHOME)/deps/mmtk/
+endif
+endif
 
 # OS specific stuff
 
diff --git a/Makefile b/Makefile
index 20d131ee8524c..b193b3849c6aa 100644
--- a/Makefile
+++ b/Makefile
@@ -281,6 +281,10 @@ endif
 endif
 endif
 
+ifneq (${MMTK_PLAN},None)
+JL_PRIVATE_LIBS-0 += libmmtk_julia
+endif
+
 # Note that we disable MSYS2's path munging here, as otherwise
 # it replaces our `:`-separated list as a `;`-separated one.
 define stringreplace
diff --git a/contrib/refresh_checksums.mk b/contrib/refresh_checksums.mk
index 5a787b0b67cb1..fa7cddc705958 100644
--- a/contrib/refresh_checksums.mk
+++ b/contrib/refresh_checksums.mk
@@ -24,7 +24,7 @@ CLANG_TRIPLETS=$(filter %-darwin %-freebsd,$(TRIPLETS))
 NON_CLANG_TRIPLETS=$(filter-out %-darwin %-freebsd,$(TRIPLETS))
 
 # These are the projects currently using BinaryBuilder; both GCC-expanded and non-GCC-expanded:
-BB_PROJECTS=openssl libssh2 nghttp2 mpfr curl libgit2 pcre libuv unwind llvmunwind dsfmt objconv p7zip zlib libsuitesparse openlibm blastrampoline libtracyclient
+BB_PROJECTS=openssl libssh2 nghttp2 mpfr curl libgit2 pcre libuv unwind llvmunwind dsfmt objconv p7zip zlib libsuitesparse openlibm blastrampoline libtracyclient mmtk_julia
 BB_GCC_EXPANDED_PROJECTS=openblas csl
 BB_CXX_EXPANDED_PROJECTS=gmp llvm clang llvm-tools lld
 # These are non-BB source-only deps
diff --git a/deps/checksums/mmtk_julia b/deps/checksums/mmtk_julia
new file mode 100644
index 0000000000000..dc8fdb9cc4ca3
--- /dev/null
+++ b/deps/checksums/mmtk_julia
@@ -0,0 +1,4 @@
+mmtk_julia-b69acf5af7a7dd97c1cc6fd99f7c2d51b477f214.tar.gz/md5/1911cf084d26c48e2ed58af3d268b4b6
+mmtk_julia-b69acf5af7a7dd97c1cc6fd99f7c2d51b477f214.tar.gz/sha512/75beab54398989c46b62e714b242cf6705d88d220f40c21e494e0f29161437f5fbe9ba05b543d2353a1ad76f4239ac4025b476be0be864649f310f14935289fe
+mmtk_julia.v0.30.2+0.x86_64-linux-gnu.tar.gz/md5/0b8d667927b7ae181245dd1aba467dcb
+mmtk_julia.v0.30.2+0.x86_64-linux-gnu.tar.gz/sha512/df45a7b148efcbf8fe24b51899bdc78f052cd96bcf43ff8e96f4ca02851589f4d634f879e2ae23e98917ba235a533a13cf0cb092bfa4fc2a48e260ae1efc007d
\ No newline at end of file
diff --git a/deps/checksums/mmtk_julia-b69acf5af7a7dd97c1cc6fd99f7c2d51b477f214.tar.gz/md5 b/deps/checksums/mmtk_julia-b69acf5af7a7dd97c1cc6fd99f7c2d51b477f214.tar.gz/md5
deleted file mode 100644
index fc6955c8f2e7b..0000000000000
--- a/deps/checksums/mmtk_julia-b69acf5af7a7dd97c1cc6fd99f7c2d51b477f214.tar.gz/md5
+++ /dev/null
@@ -1 +0,0 @@
-1911cf084d26c48e2ed58af3d268b4b6
diff --git a/deps/checksums/mmtk_julia-b69acf5af7a7dd97c1cc6fd99f7c2d51b477f214.tar.gz/sha512 b/deps/checksums/mmtk_julia-b69acf5af7a7dd97c1cc6fd99f7c2d51b477f214.tar.gz/sha512
deleted file mode 100644
index ea916976895a3..0000000000000
--- a/deps/checksums/mmtk_julia-b69acf5af7a7dd97c1cc6fd99f7c2d51b477f214.tar.gz/sha512
+++ /dev/null
@@ -1 +0,0 @@
-75beab54398989c46b62e714b242cf6705d88d220f40c21e494e0f29161437f5fbe9ba05b543d2353a1ad76f4239ac4025b476be0be864649f310f14935289fe
diff --git a/deps/mmtk/mmtk.h b/deps/mmtk/mmtk.h
new file mode 100644
index 0000000000000..c88204a769c41
--- /dev/null
+++ b/deps/mmtk/mmtk.h
@@ -0,0 +1,113 @@
+#ifndef MMTK_H
+#define MMTK_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef void* MMTk_Mutator;
+typedef void* MMTk_TraceLocal;
+typedef void (*ProcessSlotFn)(void* closure, void* slot);
+typedef void (*ProcessOffsetSlotFn)(void* closure, void* slot, int offset);
+
+typedef struct {
+    void** ptr;
+    size_t cap;
+} RootsWorkBuffer;
+
+typedef struct {
+    RootsWorkBuffer (*report_slots_func)(void** buf, size_t size, size_t cap, void* data, bool renew);
+    RootsWorkBuffer (*report_nodes_func)(void** buf, size_t size, size_t cap, void* data, bool renew);
+    RootsWorkBuffer (*report_tpinned_nodes_func)(void** buf, size_t size, size_t cap, void* data, bool renew);
+    void* data;
+} RootsWorkClosure;
+
+/**
+ * Allocation
+ */
+extern MMTk_Mutator mmtk_bind_mutator(void *tls, int tid);
+extern void mmtk_post_bind_mutator(MMTk_Mutator mutator, MMTk_Mutator original_mutator);
+extern void mmtk_destroy_mutator(MMTk_Mutator mutator);
+
+extern void* mmtk_alloc(MMTk_Mutator mutator, size_t size,
+    size_t align, size_t offset, int allocator);
+
+extern void* mmtk_alloc_large(MMTk_Mutator mutator, size_t size,
+    size_t align, size_t offset, int allocator);
+
+extern void mmtk_post_alloc(MMTk_Mutator mutator, void* refer,
+    size_t bytes, int allocator);
+
+extern bool mmtk_is_live_object(void* ref);
+extern bool mmtk_is_mapped_object(void* ref);
+extern bool mmtk_is_mapped_address(void* addr);
+extern int mmtk_object_is_managed_by_mmtk(void* addr);
+extern void mmtk_runtime_panic(void);
+extern void mmtk_unreachable(void);
+extern unsigned char mmtk_pin_object(void* obj);
+extern bool mmtk_is_pinned(void* obj);
+extern const char* get_mmtk_version(void);
+
+extern void mmtk_set_vm_space(void* addr, size_t size);
+extern void mmtk_immortal_region_post_alloc(void* addr, size_t size);
+
+// Write barriers
+extern void mmtk_memory_region_copy(MMTk_Mutator mutator, void* src_obj, void* src_addr, void* dst_obj, void* dst_addr, size_t size);
+extern void mmtk_object_reference_write_post(MMTk_Mutator mutator, const void* src, const void* target);
+extern void mmtk_object_reference_write_slow(MMTk_Mutator mutator, const void* src, const void* target);
+extern const void* MMTK_SIDE_LOG_BIT_BASE_ADDRESS;
+
+extern _Atomic(uintptr_t) JULIA_MALLOC_BYTES;
+
+/**
+ * Misc
+ */
+extern void mmtk_gc_init(uintptr_t min_heap_size, uintptr_t max_heap_size, uintptr_t n_gcthreads, uintptr_t header_size, uintptr_t tag);
+extern bool mmtk_will_never_move(void* object);
+extern bool mmtk_process(char* name, char* value);
+extern void mmtk_scan_region(void);
+extern void mmtk_handle_user_collection_request(void *tls, uint8_t collection);
+extern void mmtk_initialize_collection(void* tls);
+extern void mmtk_start_control_collector(void *tls);
+extern void mmtk_start_worker(void *tls, void* worker, void* mmtk);
+extern void mmtk_process_julia_obj(void* addr);
+extern void mmtk_register_finalizer(void* obj, void* function, bool is_ptr);
+extern void mmtk_run_finalizers_for_obj(void* obj);
+extern void mmtk_run_finalizers(bool at_exit);
+extern void mmtk_gc_poll(void *tls);
+extern void mmtk_julia_copy_stack_check(int copy_stack);
+extern void* mmtk_get_possibly_forwarded(void* object);
+extern void mmtk_block_thread_for_gc(void);
+extern void* mmtk_new_mutator_iterator(void);
+extern void* mmtk_get_next_mutator_tls(void*);
+extern void* mmtk_close_mutator_iterator(void*);
+
+
+/**
+ * VM Accounting
+ */
+extern size_t mmtk_free_bytes(void);
+extern size_t mmtk_total_bytes(void);
+extern size_t mmtk_used_bytes(void);
+extern void* mmtk_starting_heap_address(void);
+extern void* mmtk_last_heap_address(void);
+
+/**
+ * Reference Processing
+ */
+extern void mmtk_add_weak_candidate(void* ref);
+extern void mmtk_add_soft_candidate(void* ref);
+extern void mmtk_add_phantom_candidate(void* ref);
+
+extern void mmtk_harness_begin(void *tls);
+extern void mmtk_harness_end(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // MMTK_H
diff --git a/deps/mmtk/mmtkMutator.h b/deps/mmtk/mmtkMutator.h
new file mode 100644
index 0000000000000..2f513406353f2
--- /dev/null
+++ b/deps/mmtk/mmtkMutator.h
@@ -0,0 +1,114 @@
+#ifndef MMTK_JULIA_MMTK_MUTATOR_H
+#define MMTK_JULIA_MMTK_MUTATOR_H
+
+// mmtk_julia_types.h refers to the types in this file.
+// So if this file is updated, make sure you regenerate Rust types for mmtk_julia_types.h.
+
+enum Allocator {
+  AllocatorDefault = 0,
+  AllocatorImmortal = 1,
+  AllocatorLos = 2,
+  AllocatorCode = 3,
+  AllocatorReadOnly = 4,
+};
+
+typedef struct {
+  void* data;
+  void* vtable;
+} RustDynPtr;
+
+// These constants should match the constants defind in mmtk::util::alloc::allocators
+#define MAX_BUMP_ALLOCATORS 6
+#define MAX_LARGE_OBJECT_ALLOCATORS 2
+#define MAX_MALLOC_ALLOCATORS 1
+#define MAX_IMMIX_ALLOCATORS 1
+#define MAX_FREE_LIST_ALLOCATORS 2
+#define MAX_MARK_COMPACT_ALLOCATORS 1
+
+// The following types should have the same layout as the types with the same name in MMTk core (Rust)
+
+typedef struct {
+  void* tls;
+  void* cursor;
+  void* limit;
+  RustDynPtr space;
+  void* context;
+} BumpAllocator;
+
+typedef struct {
+  void* tls;
+  void* space;
+  void* context;
+} LargeObjectAllocator;
+
+typedef struct {
+  void* tls;
+  void* cursor;
+  void* limit;
+  void* immix_space;
+  void* context;
+  uint8_t hot;
+  uint8_t copy;
+  void* large_cursor;
+  void* large_limit;
+  uint8_t request_for_large;
+  uint8_t _align[7];
+  uint8_t line_opt_tag;
+  uintptr_t line_opt;
+} ImmixAllocator;
+
+typedef struct {
+  void* Address;
+} FLBlock;
+
+typedef struct {
+  FLBlock first;
+  FLBlock last;
+  size_t size;
+  char lock;
+} FLBlockList;
+
+typedef struct {
+  void* tls;
+  void* space;
+  void* context;
+  FLBlockList* available_blocks;
+  FLBlockList* available_blocks_stress;
+  FLBlockList* unswept_blocks;
+  FLBlockList* consumed_blocks;
+} FreeListAllocator;
+
+typedef struct {
+  void* tls;
+  void* space;
+  void* context;
+} MMTkMallocAllocator; // Prefix with MMTk to avoid name clash
+
+typedef struct {
+  BumpAllocator bump_allocator;
+} MarkCompactAllocator;
+
+typedef struct {
+  BumpAllocator bump_pointer[MAX_BUMP_ALLOCATORS];
+  LargeObjectAllocator large_object[MAX_LARGE_OBJECT_ALLOCATORS];
+  MMTkMallocAllocator malloc[MAX_MALLOC_ALLOCATORS];
+  ImmixAllocator immix[MAX_IMMIX_ALLOCATORS];
+  FreeListAllocator free_list[MAX_FREE_LIST_ALLOCATORS];
+  MarkCompactAllocator markcompact[MAX_MARK_COMPACT_ALLOCATORS];
+} Allocators;
+
+typedef struct {
+  void* allocator_mapping;
+  void* space_mapping;
+  RustDynPtr prepare_func;
+  RustDynPtr release_func;
+} MutatorConfig;
+
+typedef struct {
+  Allocators allocators;
+  RustDynPtr barrier;
+  void* mutator_tls;
+  RustDynPtr plan;
+  MutatorConfig config;
+} MMTkMutatorContext;
+#endif // MMTK_MUTATOR_HPP
diff --git a/deps/mmtk_julia.mk b/deps/mmtk_julia.mk
index ccf638e9211bb..7e075b6b3b531 100644
--- a/deps/mmtk_julia.mk
+++ b/deps/mmtk_julia.mk
@@ -6,6 +6,8 @@
 MMTK_MOVING := 0
 MMTK_VARS := MMTK_PLAN=$(MMTK_PLAN) MMTK_MOVING=$(MMTK_MOVING)
 
+ifneq ($(USE_BINARYBUILDER_MMTK_JULIA),1)
+
 # Download the binding, build it from source
 ifeq (${MMTK_JULIA_DIR},$(BUILDROOT)/usr/lib/mmtk_julia)
 $(eval $(call git-external,mmtk_julia,MMTK_JULIA,,,$(BUILDDIR)))
@@ -69,3 +71,10 @@ $(build_prefix)/manifest/mmtk_julia: $(BUILDROOT)/usr/lib/libmmtk_julia.so
 	@echo $(UNINSTALL_mmtk_julia) > $@
 
 endif # MMTK_JULIA_DIR
+
+else
+# We are building using the BinaryBuilder version of the binding
+
+$(eval $(call bb-install,mmtk_julia,MMTK_JULIA,false))
+
+endif # USE_BINARYBUILDER_MMTK_JULIA
diff --git a/deps/mmtk_julia.version b/deps/mmtk_julia.version
index 60f7cffe7b4de..74df4b3de61cc 100644
--- a/deps/mmtk_julia.version
+++ b/deps/mmtk_julia.version
@@ -2,3 +2,6 @@ MMTK_JULIA_BRANCH = master
 MMTK_JULIA_SHA1 = b69acf5af7a7dd97c1cc6fd99f7c2d51b477f214
 MMTK_JULIA_GIT_URL := https://github.com/mmtk/mmtk-julia.git
 MMTK_JULIA_TAR_URL = https://github.com/mmtk/mmtk-julia/archive/refs/tags/v0.30.2.tar.gz
+
+MMTK_JULIA_JLL_VER := 0.30.2+0
+MMTK_JULIA_JLL_NAME := mmtk_julia