diff --git a/include/git2/oid.h b/include/git2/oid.h
index 8d93e79cf..288e90bc8 100644
--- a/include/git2/oid.h
+++ b/include/git2/oid.h
@@ -154,19 +154,7 @@ GIT_EXTERN(int) git_oid_compare(const git_oid *oid_a, const git_oid *oid_b);
  * @param b second oid structure.
  * @return <0, 0, >0 if a < b, a == b, a > b.
  */
-GIT_INLINE(int) git_oid_cmp(const git_oid *a, const git_oid *b)
-{
-	const unsigned char *sha1 = a->id;
-	const unsigned char *sha2 = b->id;
-	int i;
-
-	for (i = 0; i < GIT_OID_RAWSZ; i++, sha1++, sha2++) {
-		if (*sha1 != *sha2)
-			return *sha1 - *sha2;
-	}
-
-	return 0;
-}
+GIT_EXTERN(int) git_oid_cmp(const git_oid *a, const git_oid *b);
 
 /**
  * Compare two oid structures for equality
diff --git a/src/attr.c b/src/attr.c
index 979fecc14..6dd2c7e2f 100644
--- a/src/attr.c
+++ b/src/attr.c
@@ -312,7 +312,7 @@ static int load_attr_blob_from_index(
 
 	entry = git_index_get_byindex(index, pos);
 
-	if (old_oid && git_oid_cmp(old_oid, &entry->oid) == 0)
+	if (old_oid && git_oid__cmp(old_oid, &entry->oid) == 0)
 		return GIT_ENOTFOUND;
 
 	if ((error = git_blob_lookup(blob, repo, &entry->oid)) < 0)
diff --git a/src/checkout.c b/src/checkout.c
index e29fccd05..96e15093c 100644
--- a/src/checkout.c
+++ b/src/checkout.c
@@ -138,7 +138,7 @@ static bool checkout_is_workdir_modified(
 		if (!sm_oid)
 			return false;
 
-		return (git_oid_cmp(&baseitem->oid, sm_oid) != 0);
+		return (git_oid__cmp(&baseitem->oid, sm_oid) != 0);
 	}
 
 	/* Look at the cache to decide if the workdir is modified.  If not,
@@ -149,7 +149,7 @@ static bool checkout_is_workdir_modified(
 		if (wditem->mtime.seconds == ie->mtime.seconds &&
 			wditem->mtime.nanoseconds == ie->mtime.nanoseconds &&
 			wditem->file_size == ie->file_size)
-			return (git_oid_cmp(&baseitem->oid, &ie->oid) != 0);
+			return (git_oid__cmp(&baseitem->oid, &ie->oid) != 0);
 	}
 
 	/* depending on where base is coming from, we may or may not know
@@ -163,7 +163,7 @@ static bool checkout_is_workdir_modified(
 			wditem->file_size, &oid) < 0)
 		return false;
 
-	return (git_oid_cmp(&baseitem->oid, &oid) != 0);
+	return (git_oid__cmp(&baseitem->oid, &oid) != 0);
 }
 
 #define CHECKOUT_ACTION_IF(FLAG,YES,NO) \
diff --git a/src/clone.c b/src/clone.c
index 0665576e3..aeb7bbf5c 100644
--- a/src/clone.c
+++ b/src/clone.c
@@ -132,14 +132,14 @@ static int reference_matches_remote_head(
 			return 0;
 	}
 
-	if (git_oid_cmp(&head_info->remote_head_oid, &oid) == 0) {
+	if (git_oid__cmp(&head_info->remote_head_oid, &oid) == 0) {
 		/* Determine the local reference name from the remote tracking one */
 		if (git_refspec_transform_l(
-			&head_info->branchname, 
+			&head_info->branchname,
 			head_info->refspec,
 			reference_name) < 0)
 				return -1;
-		
+
 		if (git_buf_len(&head_info->branchname) > 0) {
 			if (git_buf_sets(
 				&head_info->branchname,
diff --git a/src/diff.c b/src/diff.c
index 881173cde..6612abf06 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -196,21 +196,21 @@ static git_diff_delta *diff_delta__last_for_item(
 	switch (delta->status) {
 	case GIT_DELTA_UNMODIFIED:
 	case GIT_DELTA_DELETED:
-		if (git_oid_cmp(&delta->old_file.oid, &item->oid) == 0)
+		if (git_oid__cmp(&delta->old_file.oid, &item->oid) == 0)
 			return delta;
 		break;
 	case GIT_DELTA_ADDED:
-		if (git_oid_cmp(&delta->new_file.oid, &item->oid) == 0)
+		if (git_oid__cmp(&delta->new_file.oid, &item->oid) == 0)
 			return delta;
 		break;
 	case GIT_DELTA_UNTRACKED:
 		if (diff->strcomp(delta->new_file.path, item->path) == 0 &&
-			git_oid_cmp(&delta->new_file.oid, &item->oid) == 0)
+			git_oid__cmp(&delta->new_file.oid, &item->oid) == 0)
 			return delta;
 		break;
 	case GIT_DELTA_MODIFIED:
-		if (git_oid_cmp(&delta->old_file.oid, &item->oid) == 0 ||
-			git_oid_cmp(&delta->new_file.oid, &item->oid) == 0)
+		if (git_oid__cmp(&delta->old_file.oid, &item->oid) == 0 ||
+			git_oid__cmp(&delta->new_file.oid, &item->oid) == 0)
 			return delta;
 		break;
 	default:
diff --git a/src/diff_output.c b/src/diff_output.c
index b8bb73bf7..4ce01bc62 100644
--- a/src/diff_output.c
+++ b/src/diff_output.c
@@ -660,7 +660,7 @@ static int diff_patch_load(
 	 */
 	if (check_if_unmodified &&
 		delta->old_file.mode == delta->new_file.mode &&
-		!git_oid_cmp(&delta->old_file.oid, &delta->new_file.oid))
+		!git_oid__cmp(&delta->old_file.oid, &delta->new_file.oid))
 	{
 		delta->status = GIT_DELTA_UNMODIFIED;
 
@@ -1388,7 +1388,7 @@ static int diff_single_apply(diff_single_data *data)
 		(has_old ? GIT_DELTA_MODIFIED : GIT_DELTA_ADDED) :
 		(has_old ? GIT_DELTA_DELETED : GIT_DELTA_UNTRACKED);
 
-	if (git_oid_cmp(&delta->new_file.oid, &delta->old_file.oid) == 0)
+	if (git_oid__cmp(&delta->new_file.oid, &delta->old_file.oid) == 0)
 		delta->status = GIT_DELTA_UNMODIFIED;
 
 	if ((error = diff_delta_is_binary_by_content(
diff --git a/src/diff_tform.c b/src/diff_tform.c
index efcb19d95..5c1a86cb9 100644
--- a/src/diff_tform.c
+++ b/src/diff_tform.c
@@ -429,7 +429,7 @@ static int similarity_measure(
 	if (GIT_MODE_TYPE(a_file->mode) != GIT_MODE_TYPE(b_file->mode))
 		return 0;
 
-	if (git_oid_cmp(&a_file->oid, &b_file->oid) == 0)
+	if (git_oid__cmp(&a_file->oid, &b_file->oid) == 0)
 		return 100;
 
 	/* update signature cache if needed */
diff --git a/src/index.c b/src/index.c
index d8ca78e52..2e2d373b5 100644
--- a/src/index.c
+++ b/src/index.c
@@ -1411,7 +1411,7 @@ static int parse_index(git_index *index, const char *buffer, size_t buffer_size)
 	/* 160-bit SHA-1 over the content of the index file before this checksum. */
 	git_oid_fromraw(&checksum_expected, (const unsigned char *)buffer);
 
-	if (git_oid_cmp(&checksum_calculated, &checksum_expected) != 0)
+	if (git_oid__cmp(&checksum_calculated, &checksum_expected) != 0)
 		return index_error_invalid("calculated checksum does not match expected");
 
 #undef seek_forward
diff --git a/src/indexer.c b/src/indexer.c
index 606771927..91b7ba5d9 100644
--- a/src/indexer.c
+++ b/src/indexer.c
@@ -9,7 +9,6 @@
 
 #include "git2/indexer.h"
 #include "git2/object.h"
-#include "git2/oid.h"
 
 #include "common.h"
 #include "pack.h"
@@ -17,6 +16,7 @@
 #include "posix.h"
 #include "pack.h"
 #include "filebuf.h"
+#include "oid.h"
 #include "oidmap.h"
 
 #define UINT31_MAX (0x7FFFFFFF)
@@ -103,7 +103,7 @@ static int objects_cmp(const void *a, const void *b)
 	const struct entry *entrya = a;
 	const struct entry *entryb = b;
 
-	return git_oid_cmp(&entrya->oid, &entryb->oid);
+	return git_oid__cmp(&entrya->oid, &entryb->oid);
 }
 
 int git_indexer_stream_new(
diff --git a/src/odb.c b/src/odb.c
index 53630dddc..2574c6789 100644
--- a/src/odb.c
+++ b/src/odb.c
@@ -764,7 +764,7 @@ attempt_lookup:
 			git__free(data);
 			data = raw.data;
 
-			if (found && git_oid_cmp(&full_oid, &found_full_oid))
+			if (found && git_oid__cmp(&full_oid, &found_full_oid))
 				return git_odb__error_ambiguous("multiple matches for prefix");
 
 			found_full_oid = full_oid;
diff --git a/src/oid.c b/src/oid.c
index c7ce6ee50..e74640c57 100644
--- a/src/oid.c
+++ b/src/oid.c
@@ -166,9 +166,9 @@ void git_oid_cpy(git_oid *out, const git_oid *src)
 	memcpy(out->id, src->id, sizeof(out->id));
 }
 
-int git_oid_compare(const git_oid *oid_a, const git_oid *oid_b)
+int git_oid_cmp(const git_oid *a, const git_oid *b)
 {
-	return git_oid_cmp(oid_a, oid_b);
+	return git_oid__cmp(a, b);
 }
 
 int git_oid_ncmp(const git_oid *oid_a, const git_oid *oid_b, size_t len)
diff --git a/src/pack.c b/src/pack.c
index 33cdf760a..f8b621ef8 100644
--- a/src/pack.c
+++ b/src/pack.c
@@ -12,8 +12,8 @@
 #include "sha1_lookup.h"
 #include "mwindow.h"
 #include "fileops.h"
+#include "oid.h"
 
-#include "git2/oid.h"
 #include <zlib.h>
 
 static int packfile_open(struct git_pack_file *p);
@@ -875,7 +875,7 @@ static int packfile_open(struct git_pack_file *p)
 
 	idx_sha1 = ((unsigned char *)p->index_map.data) + p->index_map.len - 40;
 
-	if (git_oid_cmp(&sha1, (git_oid *)idx_sha1) == 0)
+	if (git_oid__cmp(&sha1, (git_oid *)idx_sha1) == 0)
 		return 0;
 
 cleanup:
@@ -1139,7 +1139,7 @@ int git_pack_entry_find(
 	if (len == GIT_OID_HEXSZ && p->num_bad_objects) {
 		unsigned i;
 		for (i = 0; i < p->num_bad_objects; i++)
-			if (git_oid_cmp(short_oid, &p->bad_object_sha1[i]) == 0)
+			if (git_oid__cmp(short_oid, &p->bad_object_sha1[i]) == 0)
 				return packfile_error("bad object found in packfile");
 	}
 
diff --git a/src/push.c b/src/push.c
index b6be1a4e1..9b1e78c8e 100644
--- a/src/push.c
+++ b/src/push.c
@@ -376,7 +376,7 @@ static int queue_differences(
 		const git_tree_entry *d_entry = git_tree_entry_byindex(delta, j);
 		int cmp = 0;
 
-		if (!git_oid_cmp(&b_entry->oid, &d_entry->oid))
+		if (!git_oid__cmp(&b_entry->oid, &d_entry->oid))
 			goto loop;
 
 		cmp = strcmp(b_entry->filename, d_entry->filename);
diff --git a/src/refs.c b/src/refs.c
index 9c6684a5a..f3a504147 100644
--- a/src/refs.c
+++ b/src/refs.c
@@ -831,7 +831,7 @@ int git_reference_cmp(git_reference *ref1, git_reference *ref2)
 	if (type1 == GIT_REF_SYMBOLIC)
 		return strcmp(ref1->target.symbolic, ref2->target.symbolic);
 
-	return git_oid_cmp(&ref1->target.oid, &ref2->target.oid);
+	return git_oid__cmp(&ref1->target.oid, &ref2->target.oid);
 }
 
 static int reference__update_terminal(
diff --git a/src/refs.h b/src/refs.h
index 97d4d2eb5..908e86f29 100644
--- a/src/refs.h
+++ b/src/refs.h
@@ -13,6 +13,7 @@
 #include "git2/refdb.h"
 #include "strmap.h"
 #include "buffer.h"
+#include "oid.h"
 
 #define GIT_REFS_DIR "refs/"
 #define GIT_REFS_HEADS_DIR GIT_REFS_DIR "heads/"
diff --git a/src/remote.c b/src/remote.c
index ffce2b6e2..306bc7356 100644
--- a/src/remote.c
+++ b/src/remote.c
@@ -845,7 +845,7 @@ static int update_tips_for_spec(git_remote *remote, git_refspec *spec, git_vecto
 		if (error == GIT_ENOTFOUND)
 			memset(&old, 0, GIT_OID_RAWSZ);
 
-		if (!git_oid_cmp(&old, &head->oid))
+		if (!git_oid__cmp(&old, &head->oid))
 			continue;
 
 		/* In autotag mode, don't overwrite any locally-existing tags */
diff --git a/src/transports/local.c b/src/transports/local.c
index 8af970eac..8b4d50c14 100644
--- a/src/transports/local.c
+++ b/src/transports/local.c
@@ -282,7 +282,7 @@ static int local_push_copy_object(
 		odb_obj_size) < 0 ||
 		odb_stream->finalize_write(&remote_odb_obj_oid, odb_stream) < 0) {
 		error = -1;
-	} else if (git_oid_cmp(&obj->id, &remote_odb_obj_oid) != 0) {
+	} else if (git_oid__cmp(&obj->id, &remote_odb_obj_oid) != 0) {
 		giterr_set(GITERR_ODB, "Error when writing object to remote odb "
 			"during local push operation. Remote odb object oid does not "
 			"match local oid.");