diff --git a/lib/prompt b/lib/prompt
index 393a9f4..0cbf199 100644
--- a/lib/prompt
+++ b/lib/prompt
@@ -48,20 +48,30 @@
 #   prompt      Text prompt for user input
 #   default     (Optional) Default value if response is empty
 #   fail_msg    (Optional) Failure message if empty input isn't valid
+#   required     (Optional) Flag to repeat prompt until user supplies value
 @go.prompt_for_input() {
   @go.validate_identifier_or_die 'Input prompt response variable name' "$1"
 
-  if [[ "$2" =~ [[:space:]]$ ]]; then
-    @go.printf '%s%s%s' "${2%?}" "${3:+ [default: $3]}" "${BASH_REMATCH[0]}" >&2
-  else
-    @go.printf '%s %s' "$2" "${3:+[default: $3] }" >&2
-  fi
-  @go.read_prompt_response "$1" "$3"
+  unset "$1"
+  while [[ -z "${!1-}" ]]; do
+    if [[ "$2" =~ [[:space:]]$ ]]; then
+      @go.printf '%s%s%s' "${2%?}" "${3:+ [default: $3]}" "${BASH_REMATCH[0]}" >&2
+    else
+      @go.printf '%s %s' "$2" "${3:+[default: $3] }" >&2
+    fi
 
-  if [[ -z "${!1}" && -n "$4" ]]; then
-    @go.printf '%s\n' "$4" >&2
-    return 1
-  fi
+    @go.read_prompt_response "$1" "${3-}"
+    if [[ "${5-}" != "required" ]]; then
+      if [[ -z "${!1}" && -n "${4-}" ]]; then
+        @go.printf '%s\n' "$4" >&2
+        return 1
+      else
+        break
+      fi
+    fi
+  done
+
+  return
 }
 
 # Prompts the user for a line of input, then validates it isn't dangerous
diff --git a/tests/prompt/prompt-for-input.bats b/tests/prompt/prompt-for-input.bats
index ea67789..06a6655 100644
--- a/tests/prompt/prompt-for-input.bats
+++ b/tests/prompt/prompt-for-input.bats
@@ -8,9 +8,10 @@ setup() {
     'declare prompt="$1"' \
     'declare default="$2"' \
     'declare fail_msg="$3"' \
+    'declare required="$4"' \
     'declare response="initial value"' \
     'declare result' \
-    '@go.prompt_for_input "response" "$prompt" "$default" "$fail_msg"' \
+    '@go.prompt_for_input "response" "$prompt" "$default" "$fail_msg" "$required"' \
     'result="$?"' \
     'printf -- "%s\n" "$response"' \
     'exit "$result"'
@@ -62,3 +63,10 @@ teardown() {
   assert_failure 'What is your quest?' \
     'Auuuuuuuugh!'
 }
+
+@test "$SUITE: re-prompts if input is required" {
+  run "$TEST_GO_SCRIPT" $'What is your quest?\n' '' '' 'required' <<< $'\n''None'
+  assert_success 'What is your quest?' \
+    'What is your quest?' \
+    'None'
+}