diff --git a/fetch-pack.c b/fetch-pack.c
index 86e9e18901..e98294d918 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -1327,7 +1327,8 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
 	packet_reader_init(&reader, fd[0], NULL, 0,
 			   PACKET_READ_CHOMP_NEWLINE |
 			   PACKET_READ_DIE_ON_ERR_PACKET);
-	if (server_supports_feature("fetch", "sideband-all", 0)) {
+	if (git_env_bool("GIT_TEST_SIDEBAND_ALL", 1) &&
+	    server_supports_feature("fetch", "sideband-all", 0)) {
 		reader.use_sideband = 1;
 		reader.me = "fetch-pack";
 	}
diff --git a/t/README b/t/README
index 28711cc508..b275c883b8 100644
--- a/t/README
+++ b/t/README
@@ -358,6 +358,11 @@ GIT_TEST_MULTI_PACK_INDEX=<boolean>, when true, forces the multi-pack-
 index to be written after every 'git repack' command, and overrides the
 'core.multiPackIndex' setting to true.
 
+GIT_TEST_SIDEBAND_ALL=<boolean>, when true, overrides the
+'uploadpack.allowSidebandAll' setting to true, and when false, forces
+fetch-pack to not request sideband-all (even if the server advertises
+sideband-all).
+
 Naming Tests
 ------------
 
diff --git a/t/lib-httpd/apache.conf b/t/lib-httpd/apache.conf
index 581c010d8f..9a6d368247 100644
--- a/t/lib-httpd/apache.conf
+++ b/t/lib-httpd/apache.conf
@@ -78,6 +78,7 @@ PassEnv GNUPGHOME
 PassEnv ASAN_OPTIONS
 PassEnv GIT_TRACE
 PassEnv GIT_CONFIG_NOSYSTEM
+PassEnv GIT_TEST_SIDEBAND_ALL
 
 SetEnvIf Git-Protocol ".*" GIT_PROTOCOL=$0
 
diff --git a/t/t5537-fetch-shallow.sh b/t/t5537-fetch-shallow.sh
index 6faf17e17a..6caf628efa 100755
--- a/t/t5537-fetch-shallow.sh
+++ b/t/t5537-fetch-shallow.sh
@@ -243,7 +243,8 @@ test_expect_success 'shallow fetches check connectivity before writing shallow f
 	       "$(git -C "$REPO" rev-parse HEAD)" \
 	       "$(git -C "$REPO" rev-parse HEAD^)" \
 	       >"$HTTPD_ROOT_PATH/one-time-sed" &&
-	test_must_fail git -C client fetch --depth=1 "$HTTPD_URL/one_time_sed/repo" \
+	test_must_fail env GIT_TEST_SIDEBAND_ALL=0 git -C client \
+		fetch --depth=1 "$HTTPD_URL/one_time_sed/repo" \
 		master:a_branch &&
 
 	# Ensure that the one-time-sed script was used.
diff --git a/t/t5701-git-serve.sh b/t/t5701-git-serve.sh
index ae79c6bbc0..fe45bf828d 100755
--- a/t/t5701-git-serve.sh
+++ b/t/t5701-git-serve.sh
@@ -14,7 +14,7 @@ test_expect_success 'test capability advertisement' '
 	0000
 	EOF
 
-	git serve --advertise-capabilities >out &&
+	GIT_TEST_SIDEBAND_ALL=0 git serve --advertise-capabilities >out &&
 	test-tool pkt-line unpack <out >actual &&
 	test_cmp expect actual
 '
diff --git a/t/t5702-protocol-v2.sh b/t/t5702-protocol-v2.sh
index 0f2b09ebb8..b491c62e3e 100755
--- a/t/t5702-protocol-v2.sh
+++ b/t/t5702-protocol-v2.sh
@@ -583,8 +583,8 @@ test_expect_success 'when server does not send "ready", expect FLUSH' '
 	test_must_fail env GIT_TRACE_PACKET="$(pwd)/log" git -C http_child \
 		-c protocol.version=2 \
 		fetch "$HTTPD_URL/one_time_sed/http_parent" 2> err &&
-	grep "fetch< acknowledgments" log &&
-	! grep "fetch< ready" log &&
+	grep "fetch< .*acknowledgments" log &&
+	! grep "fetch< .*ready" log &&
 	test_i18ngrep "expected no other sections to be sent after no .ready." err
 '
 
diff --git a/upload-pack.c b/upload-pack.c
index 765b7695d2..0c1feccaab 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -1288,7 +1288,9 @@ static void process_args(struct packet_reader *request,
 			continue;
 		}
 
-		if (allow_sideband_all && !strcmp(arg, "sideband-all")) {
+		if ((git_env_bool("GIT_TEST_SIDEBAND_ALL", 0) ||
+		     allow_sideband_all) &&
+		    !strcmp(arg, "sideband-all")) {
 			data->writer.use_sideband = 1;
 			continue;
 		}
@@ -1521,10 +1523,11 @@ int upload_pack_advertise(struct repository *r,
 		    allow_ref_in_want)
 			strbuf_addstr(value, " ref-in-want");
 
-		if (!repo_config_get_bool(the_repository,
-					 "uploadpack.allowsidebandall",
-					 &allow_sideband_all_value) &&
-		    allow_sideband_all_value)
+		if (git_env_bool("GIT_TEST_SIDEBAND_ALL", 0) ||
+		    (!repo_config_get_bool(the_repository,
+					   "uploadpack.allowsidebandall",
+					   &allow_sideband_all_value) &&
+		     allow_sideband_all_value))
 			strbuf_addstr(value, " sideband-all");
 	}