diff --git a/Documentation/git.txt b/Documentation/git.txt
index 73dc0ad0a0..179615195f 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -913,6 +913,10 @@ for further details.
 	and read the password from its STDOUT. See also the 'core.askpass'
 	option in linkgit:git-config[1].
 
+'GIT_TERMINAL_PROMPT'::
+	If this environment variable is set to `0`, git will not prompt
+	on the terminal (e.g., when asking for HTTP authentication).
+
 'GIT_CONFIG_NOSYSTEM'::
 	Whether to skip reading settings from the system-wide
 	`$(prefix)/etc/gitconfig` file.  This environment variable can
diff --git a/Documentation/technical/api-credentials.txt b/Documentation/technical/api-credentials.txt
index c1b42a40d3..e44426dd04 100644
--- a/Documentation/technical/api-credentials.txt
+++ b/Documentation/technical/api-credentials.txt
@@ -248,7 +248,10 @@ FORMAT` in linkgit:git-credential[7] for a detailed specification).
 For a `get` operation, the helper should produce a list of attributes
 on stdout in the same format. A helper is free to produce a subset, or
 even no values at all if it has nothing useful to provide. Any provided
-attributes will overwrite those already known about by Git.
+attributes will overwrite those already known about by Git.  If a helper
+outputs a `quit` attribute with a value of `true` or `1`, no further
+helpers will be consulted, nor will the user be prompted (if no
+credential has been provided, the operation will then fail).
 
 For a `store` or `erase` operation, the helper's output is ignored.
 If it fails to perform the requested operation, it may complain to
diff --git a/credential.c b/credential.c
index 1886ea50b3..b146ad8481 100644
--- a/credential.c
+++ b/credential.c
@@ -173,6 +173,8 @@ int credential_read(struct credential *c, FILE *fp)
 			c->path = xstrdup(value);
 		} else if (!strcmp(key, "url")) {
 			credential_from_url(c, value);
+		} else if (!strcmp(key, "quit")) {
+			c->quit = !!git_config_bool("quit", value);
 		}
 		/*
 		 * Ignore other lines; we don't know what they mean, but
@@ -274,6 +276,9 @@ void credential_fill(struct credential *c)
 		credential_do(c, c->helpers.items[i].string, "get");
 		if (c->username && c->password)
 			return;
+		if (c->quit)
+			die("credential helper '%s' told us to quit",
+			    c->helpers.items[i].string);
 	}
 
 	credential_getpass(c);
diff --git a/credential.h b/credential.h
index 0c3e85e8e4..6b0cd16be2 100644
--- a/credential.h
+++ b/credential.h
@@ -7,6 +7,7 @@ struct credential {
 	struct string_list helpers;
 	unsigned approved:1,
 		 configured:1,
+		 quit:1,
 		 use_http_path:1;
 
 	char *username;
diff --git a/prompt.c b/prompt.c
index e5b4938efc..8181eebbfc 100644
--- a/prompt.c
+++ b/prompt.c
@@ -57,11 +57,19 @@ char *git_prompt(const char *prompt, int flags)
 			r = do_askpass(askpass, prompt);
 	}
 
-	if (!r)
-		r = git_terminal_prompt(prompt, flags & PROMPT_ECHO);
 	if (!r) {
-		/* prompts already contain ": " at the end */
-		die("could not read %s%s", prompt, strerror(errno));
+		const char *err;
+
+		if (git_env_bool("GIT_TERMINAL_PROMPT", 1)) {
+			r = git_terminal_prompt(prompt, flags & PROMPT_ECHO);
+			err = strerror(errno);
+		} else {
+			err = "terminal prompts disabled";
+		}
+		if (!r) {
+			/* prompts already contain ": " at the end */
+			die("could not read %s%s", prompt, err);
+		}
 	}
 	return r;
 }
diff --git a/t/t0300-credentials.sh b/t/t0300-credentials.sh
index 57ea5a10c5..d7ef44b4a2 100755
--- a/t/t0300-credentials.sh
+++ b/t/t0300-credentials.sh
@@ -289,4 +289,13 @@ test_expect_success 'http paths can be part of context' '
 	EOF
 '
 
+test_expect_success 'helpers can abort the process' '
+	test_must_fail git \
+		-c credential.helper="!f() { echo quit=1; }; f" \
+		-c credential.helper="verbatim foo bar" \
+		credential fill >stdout &&
+	>expect &&
+	test_cmp expect stdout
+'
+
 test_done