diff --git a/src/ruby/ext/grpc/rb_call.c b/src/ruby/ext/grpc/rb_call.c
index 1b1958fd26337a016188520fcb712dcf277baf97..b0963411d1a2b5ec1dca9bf63e6195f68a51d4ab 100644
--- a/src/ruby/ext/grpc/rb_call.c
+++ b/src/ruby/ext/grpc/rb_call.c
@@ -42,6 +42,17 @@
 #include "rb_completion_queue.h"
 #include "rb_grpc.h"
 
+/* grpc_rb_cCall is the Call class whose instances proxy grpc_call. */
+static VALUE grpc_rb_cCall;
+
+/* grpc_rb_eCallError is the ruby class of the exception thrown during call
+   operations; */
+VALUE grpc_rb_eCallError = Qnil;
+
+/* grpc_rb_eOutOfTime is the ruby class of the exception thrown to indicate
+   a timeout. */
+static VALUE grpc_rb_eOutOfTime = Qnil;
+
 /* grpc_rb_sBatchResult is struct class used to hold the results of a batch
  * call. */
 static VALUE grpc_rb_sBatchResult;
@@ -86,7 +97,7 @@ static VALUE sym_cancelled;
 static VALUE hash_all_calls;
 
 /* Destroys a Call. */
-void grpc_rb_call_destroy(void *p) {
+static void grpc_rb_call_destroy(void *p) {
   grpc_call *call = NULL;
   VALUE ref_count = Qnil;
   if (p == NULL) {
@@ -188,7 +199,7 @@ static VALUE grpc_rb_call_set_metadata(VALUE self, VALUE metadata) {
    it's capacity should have been computed via a prior call to
    grpc_rb_md_ary_fill_hash_cb
 */
-int grpc_rb_md_ary_fill_hash_cb(VALUE key, VALUE val, VALUE md_ary_obj) {
+static int grpc_rb_md_ary_fill_hash_cb(VALUE key, VALUE val, VALUE md_ary_obj) {
   grpc_metadata_array *md_ary = NULL;
   int array_length;
   int i;
@@ -227,7 +238,8 @@ int grpc_rb_md_ary_fill_hash_cb(VALUE key, VALUE val, VALUE md_ary_obj) {
 /* grpc_rb_md_ary_capacity_hash_cb is the hash iteration callback used
    to pre-compute the capacity a grpc_metadata_array.
 */
-int grpc_rb_md_ary_capacity_hash_cb(VALUE key, VALUE val, VALUE md_ary_obj) {
+static int grpc_rb_md_ary_capacity_hash_cb(VALUE key, VALUE val,
+                                           VALUE md_ary_obj) {
   grpc_metadata_array *md_ary = NULL;
 
   /* Construct a metadata object from key and value and add it */
@@ -245,7 +257,7 @@ int grpc_rb_md_ary_capacity_hash_cb(VALUE key, VALUE val, VALUE md_ary_obj) {
 /* grpc_rb_md_ary_convert converts a ruby metadata hash into
    a grpc_metadata_array.
 */
-void grpc_rb_md_ary_convert(VALUE md_ary_hash, grpc_metadata_array *md_ary) {
+static void grpc_rb_md_ary_convert(VALUE md_ary_hash, grpc_metadata_array *md_ary) {
   VALUE md_ary_obj = Qnil;
   if (md_ary_hash == Qnil) {
     return;  /* Do nothing if the expected has value is nil */
@@ -301,7 +313,8 @@ VALUE grpc_rb_md_ary_to_h(grpc_metadata_array *md_ary) {
 /* grpc_rb_call_check_op_keys_hash_cb is a hash iteration func that checks
    each key of an ops hash is valid.
 */
-int grpc_rb_call_check_op_keys_hash_cb(VALUE key, VALUE val, VALUE ops_ary) {
+static int grpc_rb_call_check_op_keys_hash_cb(VALUE key, VALUE val,
+                                              VALUE ops_ary) {
   /* Update the capacity; the value is an array, add capacity for each value in
    * the array */
   if (TYPE(key) != T_FIXNUM) {
@@ -330,7 +343,7 @@ int grpc_rb_call_check_op_keys_hash_cb(VALUE key, VALUE val, VALUE ops_ary) {
 /* grpc_rb_op_update_status_from_server adds the values in a ruby status
    struct to the 'send_status_from_server' portion of an op.
 */
-void grpc_rb_op_update_status_from_server(grpc_op *op,
+static void grpc_rb_op_update_status_from_server(grpc_op *op,
                                           grpc_metadata_array* md_ary,
                                           VALUE status) {
   VALUE code = rb_struct_aref(status, sym_code);
@@ -582,18 +595,7 @@ static VALUE grpc_rb_call_run_batch(VALUE self, VALUE cqueue, VALUE tag,
   return result;
 }
 
-/* grpc_rb_cCall is the ruby class that proxies grpc_call. */
-VALUE grpc_rb_cCall = Qnil;
-
-/* grpc_rb_eCallError is the ruby class of the exception thrown during call
-   operations; */
-VALUE grpc_rb_eCallError = Qnil;
-
-/* grpc_rb_eOutOfTime is the ruby class of the exception thrown to indicate
-   a timeout. */
-VALUE grpc_rb_eOutOfTime = Qnil;
-
-void Init_grpc_error_codes() {
+static void Init_grpc_error_codes() {
   /* Constants representing the error codes of grpc_call_error in grpc.h */
   VALUE grpc_rb_mRpcErrors =
       rb_define_module_under(grpc_rb_mGrpcCore, "RpcErrors");
@@ -645,7 +647,7 @@ void Init_grpc_error_codes() {
   rb_obj_freeze(rb_error_code_details);
 }
 
-void Init_grpc_op_codes() {
+static void Init_grpc_op_codes() {
   /* Constants representing operation type codes in grpc.h */
   VALUE grpc_rb_mCallOps =
       rb_define_module_under(grpc_rb_mGrpcCore, "CallOps");
diff --git a/src/ruby/ext/grpc/rb_call.h b/src/ruby/ext/grpc/rb_call.h
index e20a34c74e27a70f2f8e8a058ec3576d24973861..003ce0429e05b98aefa98009721d795826ecfd48 100644
--- a/src/ruby/ext/grpc/rb_call.h
+++ b/src/ruby/ext/grpc/rb_call.h
@@ -49,17 +49,10 @@ const char* grpc_call_error_detail_of(grpc_call_error err);
 /* Converts a metadata array to a hash. */
 VALUE grpc_rb_md_ary_to_h(grpc_metadata_array *md_ary);
 
-/* grpc_rb_cCall is the Call class whose instances proxy grpc_call. */
-extern VALUE grpc_rb_cCall;
-
 /* grpc_rb_eCallError is the ruby class of the exception thrown during call
    operations. */
 extern VALUE grpc_rb_eCallError;
 
-/* grpc_rb_eOutOfTime is the ruby class of the exception thrown to indicate
-   a timeout. */
-extern VALUE grpc_rb_eOutOfTime;
-
 /* Initializes the Call class. */
 void Init_grpc_call();
 
diff --git a/src/ruby/ext/grpc/rb_channel.c b/src/ruby/ext/grpc/rb_channel.c
index 3480280a03cab1e3fd08c6980763b1b3f02824c4..9bd7c2edf99672a1b883d912979d6bb8993855b0 100644
--- a/src/ruby/ext/grpc/rb_channel.c
+++ b/src/ruby/ext/grpc/rb_channel.c
@@ -58,6 +58,8 @@ static ID id_target;
  * GCed before the channel */
 static ID id_cqueue;
 
+/* grpc_rb_cChannel is the ruby class that proxies grpc_channel. */
+static VALUE grpc_rb_cChannel = Qnil;
 
 /* Used during the conversion of a hash to channel args during channel setup */
 static VALUE grpc_rb_cChannelArgs;
@@ -240,9 +242,6 @@ static VALUE grpc_rb_channel_destroy(VALUE self) {
   return Qnil;
 }
 
-/* grpc_rb_cChannel is the ruby class that proxies grpc_channel. */
-VALUE grpc_rb_cChannel = Qnil;
-
 void Init_grpc_channel() {
   grpc_rb_cChannelArgs = rb_define_class("TmpChannelArgs", rb_cObject);
   grpc_rb_cChannel =
diff --git a/src/ruby/ext/grpc/rb_channel.h b/src/ruby/ext/grpc/rb_channel.h
index 5c57b31fb2831ad740c42cbc90834a15abd49582..6e3c087689e70ce1c2583f94c3d44492ce8fd35a 100644
--- a/src/ruby/ext/grpc/rb_channel.h
+++ b/src/ruby/ext/grpc/rb_channel.h
@@ -37,9 +37,6 @@
 #include <ruby.h>
 #include <grpc/grpc.h>
 
-/* grpc_rb_cChannel is the Channel class whose instances proxy grpc_channel. */
-extern VALUE grpc_rb_cChannel;
-
 /* Initializes the Channel class. */
 void Init_grpc_channel();
 
diff --git a/src/ruby/ext/grpc/rb_completion_queue.c b/src/ruby/ext/grpc/rb_completion_queue.c
index 20ce1b909c16ccc388c42e752f8a24b1e127d25b..a72f01ffb86f436efa384c15f934c4cd958fa733 100644
--- a/src/ruby/ext/grpc/rb_completion_queue.c
+++ b/src/ruby/ext/grpc/rb_completion_queue.c
@@ -39,6 +39,10 @@
 #include <grpc/support/time.h>
 #include "rb_grpc.h"
 
+/* grpc_rb_cCompletionQueue is the ruby class that proxies
+ * grpc_completion_queue. */
+static VALUE grpc_rb_cCompletionQueue = Qnil;
+
 /* Used to allow grpc_completion_queue_next call to release the GIL */
 typedef struct next_call_stack {
   grpc_completion_queue *cq;
@@ -166,10 +170,6 @@ grpc_event* grpc_rb_completion_queue_pluck_event(VALUE self, VALUE tag,
   return next_call.event;
 }
 
-/* grpc_rb_cCompletionQueue is the ruby class that proxies
- * grpc_completion_queue. */
-VALUE grpc_rb_cCompletionQueue = Qnil;
-
 void Init_grpc_completion_queue() {
   grpc_rb_cCompletionQueue =
       rb_define_class_under(grpc_rb_mGrpcCore, "CompletionQueue", rb_cObject);
diff --git a/src/ruby/ext/grpc/rb_completion_queue.h b/src/ruby/ext/grpc/rb_completion_queue.h
index 1bfb80e49950bbc8d14aedc06b445307e7f6dc2d..4d0f49ac478290ee151d597ee639bb1b342b3ffc 100644
--- a/src/ruby/ext/grpc/rb_completion_queue.h
+++ b/src/ruby/ext/grpc/rb_completion_queue.h
@@ -48,10 +48,6 @@ grpc_completion_queue *grpc_rb_get_wrapped_completion_queue(VALUE v);
 grpc_event* grpc_rb_completion_queue_pluck_event(VALUE cqueue, VALUE tag,
                                                  VALUE timeout);
 
-/* grpc_rb_cCompletionQueue is the CompletionQueue class whose instances proxy
-   grpc_completion_queue. */
-extern VALUE grpc_rb_cCompletionQueue;
-
 /* Initializes the CompletionQueue class. */
 void Init_grpc_completion_queue();
 
diff --git a/src/ruby/ext/grpc/rb_credentials.c b/src/ruby/ext/grpc/rb_credentials.c
index 1504a4884ea3a47dc3b0c424ed62bce8e35fdc1e..122cffc92f1c6be40d8914f43be025117dc49032 100644
--- a/src/ruby/ext/grpc/rb_credentials.c
+++ b/src/ruby/ext/grpc/rb_credentials.c
@@ -40,6 +40,9 @@
 
 #include "rb_grpc.h"
 
+/* grpc_rb_cCredentials is the ruby class that proxies grpc_credentials. */
+static VALUE grpc_rb_cCredentials = Qnil;
+
 /* grpc_rb_credentials wraps a grpc_credentials.  It provides a
  * peer ruby object, 'mark' to minimize copying when a credential is
  * created from ruby. */
@@ -242,9 +245,6 @@ static VALUE grpc_rb_credentials_init(int argc, VALUE *argv, VALUE self) {
   return self;
 }
 
-/* grpc_rb_cCredentials is the ruby class that proxies grpc_credentials. */
-VALUE grpc_rb_cCredentials = Qnil;
-
 void Init_grpc_credentials() {
   grpc_rb_cCredentials =
       rb_define_class_under(grpc_rb_mGrpcCore, "Credentials", rb_cObject);
diff --git a/src/ruby/ext/grpc/rb_credentials.h b/src/ruby/ext/grpc/rb_credentials.h
index dc0a3d01e81b99194534f412dade71747c552369..e7c43c9c781909e198ece24e4e2411af2daa8a48 100644
--- a/src/ruby/ext/grpc/rb_credentials.h
+++ b/src/ruby/ext/grpc/rb_credentials.h
@@ -37,10 +37,6 @@
 #include <ruby.h>
 #include <grpc/grpc_security.h>
 
-/* grpc_rb_cCredentials is the ruby class whose instances proxy
-   grpc_credentials. */
-extern VALUE grpc_rb_cCredentials;
-
 /* Initializes the ruby Credentials class. */
 void Init_grpc_credentials();
 
diff --git a/src/ruby/ext/grpc/rb_grpc.c b/src/ruby/ext/grpc/rb_grpc.c
index 4f30a6216a3514727dedefb694d3da8ded98df8a..1cbd1aa8bde2dd254648642932e9438a95593c29 100644
--- a/src/ruby/ext/grpc/rb_grpc.c
+++ b/src/ruby/ext/grpc/rb_grpc.c
@@ -50,7 +50,7 @@
 const RUBY_DATA_FUNC GC_NOT_MARKED = NULL;
 const RUBY_DATA_FUNC GC_DONT_FREE = NULL;
 
-VALUE grpc_rb_cTimeVal = Qnil;
+static VALUE grpc_rb_cTimeVal = Qnil;
 
 /* Alloc func that blocks allocation of a given object by raising an
  * exception. */
@@ -150,7 +150,7 @@ gpr_timespec grpc_rb_time_timeval(VALUE time, int interval) {
   return t;
 }
 
-void Init_grpc_status_codes() {
+static void Init_grpc_status_codes() {
   /* Constants representing the status codes or grpc_status_code in status.h */
   VALUE grpc_rb_mStatusCodes =
       rb_define_module_under(grpc_rb_mGrpcCore, "StatusCodes");
@@ -199,7 +199,7 @@ static ID id_inspect;
 static ID id_to_s;
 
 /* Converts a wrapped time constant to a standard time. */
-VALUE grpc_rb_time_val_to_time(VALUE self) {
+static VALUE grpc_rb_time_val_to_time(VALUE self) {
   gpr_timespec *time_const = NULL;
   Data_Get_Struct(self, gpr_timespec, time_const);
   return rb_funcall(rb_cTime, id_at, 2, INT2NUM(time_const->tv_sec),
@@ -207,17 +207,17 @@ VALUE grpc_rb_time_val_to_time(VALUE self) {
 }
 
 /* Invokes inspect on the ctime version of the time val. */
-VALUE grpc_rb_time_val_inspect(VALUE self) {
+static VALUE grpc_rb_time_val_inspect(VALUE self) {
   return rb_funcall(grpc_rb_time_val_to_time(self), id_inspect, 0);
 }
 
 /* Invokes to_s on the ctime version of the time val. */
-VALUE grpc_rb_time_val_to_s(VALUE self) {
+static VALUE grpc_rb_time_val_to_s(VALUE self) {
   return rb_funcall(grpc_rb_time_val_to_time(self), id_to_s, 0);
 }
 
 /* Adds a module with constants that map to gpr's static timeval structs. */
-void Init_grpc_time_consts() {
+static void Init_grpc_time_consts() {
   VALUE grpc_rb_mTimeConsts =
       rb_define_module_under(grpc_rb_mGrpcCore, "TimeConsts");
   grpc_rb_cTimeVal =
@@ -244,7 +244,7 @@ void Init_grpc_time_consts() {
   id_tv_nsec = rb_intern("tv_nsec");
 }
 
-void grpc_rb_shutdown(void *vm) { grpc_shutdown(); }
+static void grpc_rb_shutdown(void *vm) { grpc_shutdown(); }
 
 /* Initialize the GRPC module structs */
 
@@ -257,6 +257,11 @@ VALUE grpc_rb_sStatus = Qnil;
 VALUE grpc_rb_mGRPC = Qnil;
 VALUE grpc_rb_mGrpcCore = Qnil;
 
+/* cached Symbols for members in Status struct */
+VALUE sym_code = Qundef;
+VALUE sym_details = Qundef;
+VALUE sym_metadata = Qundef;
+
 void Init_grpc() {
   grpc_init();
   ruby_vm_at_exit(grpc_rb_shutdown);
diff --git a/src/ruby/ext/grpc/rb_grpc.h b/src/ruby/ext/grpc/rb_grpc.h
index 3a93029556f53997f305794abfad72048f1c165f..1d411baf5b4280f7efbb449b38297f04df8525cd 100644
--- a/src/ruby/ext/grpc/rb_grpc.h
+++ b/src/ruby/ext/grpc/rb_grpc.h
@@ -41,9 +41,6 @@
 /* grpc_rb_mGrpcCore is the module containing the ruby wrapper GRPC classes. */
 extern VALUE grpc_rb_mGrpcCore;
 
-/* Class used to wrap timeval structs. */
-extern VALUE grpc_rb_cTimeVal;
-
 /* grpc_rb_sNewServerRpc is the struct that holds new server rpc details. */
 extern VALUE grpc_rb_sNewServerRpc;
 
@@ -51,13 +48,13 @@ extern VALUE grpc_rb_sNewServerRpc;
 extern VALUE grpc_rb_sStatus;
 
 /* sym_code is the symbol for the code attribute of grpc_rb_sStatus. */
-VALUE sym_code;
+extern VALUE sym_code;
 
 /* sym_details is the symbol for the details attribute of grpc_rb_sStatus. */
-VALUE sym_details;
+extern VALUE sym_details;
 
 /* sym_metadata is the symbol for the metadata attribute of grpc_rb_sStatus. */
-VALUE sym_metadata;
+extern VALUE sym_metadata;
 
 /* GC_NOT_MARKED is used in calls to Data_Wrap_Struct to indicate that the
    wrapped struct does not need to participate in ruby gc. */
diff --git a/src/ruby/ext/grpc/rb_server.c b/src/ruby/ext/grpc/rb_server.c
index 33d9d695008de2adbff78b2a324a03fc6a3418ac..80f7760ebb652cc91b614dc5efd6f59bb8ca148b 100644
--- a/src/ruby/ext/grpc/rb_server.c
+++ b/src/ruby/ext/grpc/rb_server.c
@@ -44,7 +44,7 @@
 #include "rb_grpc.h"
 
 /* grpc_rb_cServer is the ruby class that proxies grpc_server. */
-VALUE grpc_rb_cServer = Qnil;
+static VALUE grpc_rb_cServer = Qnil;
 
 /* id_at is the constructor method of the ruby standard Time class. */
 static ID id_at;
diff --git a/src/ruby/ext/grpc/rb_server.h b/src/ruby/ext/grpc/rb_server.h
index 22e88a7d46e9eb52f172bee882802b9e1b93d48c..5e4b711d35b8816eb11cd87d3d280c7baa79e4cd 100644
--- a/src/ruby/ext/grpc/rb_server.h
+++ b/src/ruby/ext/grpc/rb_server.h
@@ -37,10 +37,6 @@
 #include <ruby.h>
 #include <grpc/grpc.h>
 
-/* grpc_rb_cServer is the Server class whose instances proxy
-   grpc_byte_buffer. */
-extern VALUE grpc_rb_cServer;
-
 /* Initializes the Server class. */
 void Init_grpc_server();
 
diff --git a/src/ruby/ext/grpc/rb_server_credentials.c b/src/ruby/ext/grpc/rb_server_credentials.c
index 8b813eaca1cfd954aef740562d3f62055a7d3342..5109b96b5f6fe3b8bfc73d59bb91f57bdc1a88a6 100644
--- a/src/ruby/ext/grpc/rb_server_credentials.c
+++ b/src/ruby/ext/grpc/rb_server_credentials.c
@@ -40,6 +40,10 @@
 
 #include "rb_grpc.h"
 
+/* grpc_rb_cServerCredentials is the ruby class that proxies
+   grpc_server_credentials. */
+static VALUE grpc_rb_cServerCredentials = Qnil;
+
 /* grpc_rb_server_credentials wraps a grpc_server_credentials.  It provides a
    peer ruby object, 'mark' to minimize copying when a server credential is
    created from ruby. */
@@ -180,10 +184,6 @@ static VALUE grpc_rb_server_credentials_init(VALUE self, VALUE pem_root_certs,
   return self;
 }
 
-/* grpc_rb_cServerCredentials is the ruby class that proxies
-   grpc_server_credentials. */
-VALUE grpc_rb_cServerCredentials = Qnil;
-
 void Init_grpc_server_credentials() {
   grpc_rb_cServerCredentials =
       rb_define_class_under(grpc_rb_mGrpcCore, "ServerCredentials", rb_cObject);
diff --git a/src/ruby/ext/grpc/rb_server_credentials.h b/src/ruby/ext/grpc/rb_server_credentials.h
index f79a8693581ebebfec22cc842e55cbe709af133e..35b395ad5ccd757081eb4a23cf816f65e2b5ae5d 100644
--- a/src/ruby/ext/grpc/rb_server_credentials.h
+++ b/src/ruby/ext/grpc/rb_server_credentials.h
@@ -37,10 +37,6 @@
 #include <ruby.h>
 #include <grpc/grpc_security.h>
 
-/* grpc_rb_cServerCredentials is the ruby class whose instances proxy
-   grpc_server_credentials. */
-extern VALUE grpc_rb_cServerCredentials;
-
 /* Initializes the ruby ServerCredentials class. */
 void Init_grpc_server_credentials();