diff --git a/lib/getopts_long.bash b/lib/getopts_long.bash
index baabf95..270caa0 100644
--- a/lib/getopts_long.bash
+++ b/lib/getopts_long.bash
@@ -37,7 +37,10 @@ getopts_long() {
     # Sanitize and normalize short optspec
     optspec_short="${optspec_short//-:}"
     optspec_short="${optspec_short//-}"
-    [[ "${!OPTIND:0:2}" == "--" ]] && optspec_short+='-:'
+    if [[ -n "${!OPTIND:-}" && "${!OPTIND:0:2}" == "--" ]]; then
+        optspec_short+='-:'
+    fi
+
 
     builtin getopts -- "${optspec_short}" "${optvar}" "${@}" || return ${?}
     [[ "${!optvar}" == '-' ]] || return 0
@@ -50,10 +53,9 @@ getopts_long() {
 
         # Missing argument
         if [[ -z "${OPTARG}" ]]; then
-            OPTARG="${!OPTIND}" && OPTIND=$(( OPTIND + 1 ))
-            [[ -z "${OPTARG}" ]] || return 0
-
-            if [[ "${optspec_short:0:1}" == ':' ]]; then
+            if [[ -n "${!OPTIND:-}" ]]; then
+                OPTARG="${!OPTIND}" && OPTIND=$(( OPTIND + 1 ))
+            elif [[ "${optspec_short:0:1}" == ':' ]]; then
                 OPTARG="${!optvar}" && printf -v "${optvar}" ':'
             else
                 [[ "${OPTERR}" == 0 ]] || \
diff --git a/test/bats/github_18.bats b/test/bats/github_18.bats
new file mode 100644
index 0000000..20b455f
--- /dev/null
+++ b/test/bats/github_18.bats
@@ -0,0 +1,42 @@
+#!/usr/bin/env bats
+
+load ../test_helper
+export GETOPTS_LONG_TEST_BIN='getopts_long-nounset'
+
+@test "${FEATURE}: toggles, silent" {
+    compare '-t -t -- user_arg' \
+            '-t --toggle -- user_arg'
+}
+@test "${FEATURE}: toggles, verbose" {
+    compare '-t -t -- user_arg' \
+            '-t --toggle -- user_arg'
+}
+
+@test "${FEATURE}: options, silent" {
+    compare '-o user_val1 -o user_val2 -- user_arg' \
+            '-o user_val1 --option user_val2 -- user_arg'
+}
+@test "${FEATURE}: options, verbose" {
+    compare '-o user_val1 -o user_val2 -- user_arg' \
+            '-o user_val1 --option user_val2 -- user_arg'
+}
+
+@test "${FEATURE}: variables, silent" {
+    compare '-vuser_val1 -vuser_val2 -- user_arg' \
+            '-vuser_val1 --variable=user_val2 -- user_arg'
+}
+@test "${FEATURE}: variables, verbose" {
+    compare '-vuser_val1 -vuser_val2 -- user_arg' \
+            '-vuser_val1 --variable=user_val2 -- user_arg'
+}
+
+@test "${FEATURE}: missing last argument, silent" {
+    compare '-vuser_val1 -vuser_val2 -- user_arg' \
+            '-vuser_val1 --variable=user_val2 -- user_arg'
+}
+@test "${FEATURE}: missing last argument, verbose" {
+    compare '-o' \
+            '--option' \
+            '1{s/getopts.+verbose:/getopts-NORMALIZED:/}' \
+            '1{s/(option requires an argument --) (o|option)$/\1 NORMALIZED/}'
+}
diff --git a/test/bin/getopts_long-explicit_args-silent b/test/bin/getopts_long-explicit_args-silent
index 355d238..cd94a3e 100755
--- a/test/bin/getopts_long-explicit_args-silent
+++ b/test/bin/getopts_long-explicit_args-silent
@@ -58,23 +58,17 @@ variables() {
     getopts_function -vuser_val1 --variable=user_val2 -- user_arg
 }
 
-enable_extdebug='false'
-if shopt -q extdebug; then
-    enable_extdebug='true'
+(
     shopt -u extdebug
-fi
 
-: "${1:?Missing required argument -- function name}"
-function_name=${1}
-shift
+    : "${1:?Missing required argument -- function name}"
+    function_name=${1}
+    shift
 
-if declare -f "$function_name" > /dev/null; then
-    ${function_name} "$@"
-else
-    echo "Function not found -- ${function_name}"
-    exit 1
-fi
-
-if ${enable_extdebug}; then
-    shopt -s extdebug
-fi
+    if declare -f "$function_name" > /dev/null; then
+        ${function_name} "$@"
+    else
+        echo "Function not found -- ${function_name}"
+        exit 1
+    fi
+)
diff --git a/test/bin/getopts_long-explicit_args-verbose b/test/bin/getopts_long-explicit_args-verbose
index 538c5f0..cea485d 100755
--- a/test/bin/getopts_long-explicit_args-verbose
+++ b/test/bin/getopts_long-explicit_args-verbose
@@ -58,23 +58,17 @@ variables() {
     getopts_function -vuser_val1 --variable=user_val2 -- user_arg
 }
 
-enable_extdebug='false'
-if shopt -q extdebug; then
-    enable_extdebug='true'
+(
     shopt -u extdebug
-fi
 
-: "${1:?Missing required parameter -- function name}"
-function_name=${1}
-shift
+    : "${1:?Missing required parameter -- function name}"
+    function_name=${1}
+    shift
 
-if declare -f "$function_name" > /dev/null; then
-    ${function_name} "$@"
-else
-    echo "Function not found -- ${function_name}"
-    exit 1
-fi
-
-if ${enable_extdebug}; then
-    shopt -s extdebug
-fi
+    if declare -f "$function_name" > /dev/null; then
+        ${function_name} "$@"
+    else
+        echo "Function not found -- ${function_name}"
+        exit 1
+    fi
+)
diff --git a/test/bin/getopts_long-nounset-silent b/test/bin/getopts_long-nounset-silent
new file mode 100755
index 0000000..56cd24c
--- /dev/null
+++ b/test/bin/getopts_long-nounset-silent
@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+
+TOPDIR="$(cd "$(dirname "${0}")"/../.. && pwd)"
+# shellcheck disable=SC1090
+source "${TOPDIR}/lib/getopts_long.bash"
+
+(
+    set -o nounset
+
+    while getopts_long ':to:v: toggle option: variable:' OPTKEY; do
+        case ${OPTKEY} in
+            't'|'toggle')
+                printf 'toggle triggered'
+                ;;
+            'o'|'option')
+                printf 'option supplied'
+                ;;
+            'v'|'variable')
+                printf 'value supplied'
+                ;;
+            '?')
+                printf "INVALID OPTION"
+                ;;
+            ':')
+                printf "MISSING ARGUMENT"
+                ;;
+            *)
+                printf "NEVER REACHED"
+                ;;
+        esac
+        printf ' -- '
+        declare -p OPTARG 2>&1 | grep -oe 'OPTARG.*'
+    done
+
+    shift $(( OPTIND - 1 ))
+
+    echo "OPTERR: ${OPTERR:-}"
+    echo "OPTKEY: ${OPTKEY:-}"
+    echo "OPTARG: ${OPTARG:-}"
+    echo "OPTIND: ${OPTIND:-}"
+
+    args=("$@")
+    declare -p args | sed -e 's/declare -a args=/$@: /'
+)
diff --git a/test/bin/getopts_long-nounset-verbose b/test/bin/getopts_long-nounset-verbose
new file mode 100755
index 0000000..1726b26
--- /dev/null
+++ b/test/bin/getopts_long-nounset-verbose
@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+
+TOPDIR="$(cd "$(dirname "${0}")"/../.. && pwd)"
+# shellcheck disable=SC1090
+source "${TOPDIR}/lib/getopts_long.bash"
+
+(
+    set -o nounset
+
+    while getopts_long 'to:v: toggle option: variable:' OPTKEY; do
+        case ${OPTKEY} in
+            't'|'toggle')
+                printf 'toggle triggered'
+                ;;
+            'o'|'option')
+                printf 'option supplied'
+                ;;
+            'v'|'variable')
+                printf 'value supplied'
+                ;;
+            '?')
+                printf "INVALID OPTION or MISSING ARGUMENT"
+                ;;
+            *)
+                printf "NEVER REACHED"
+                ;;
+        esac
+        printf ' -- '
+        declare -p OPTARG 2>&1 | grep -oe 'OPTARG.*'
+    done
+
+    shift $(( OPTIND - 1 ))
+
+    echo "OPTERR: ${OPTERR:-}"
+    echo "OPTKEY: ${OPTKEY:-}"
+    echo "OPTARG: ${OPTARG:-}"
+    echo "OPTIND: ${OPTIND:-}"
+
+    args=("$@")
+    declare -p args | sed -e 's/declare -a args=/$@: /'
+)
diff --git a/test/bin/getopts_long-with_extdebug-silent b/test/bin/getopts_long-with_extdebug-silent
index 45c0fda..b1ce67b 100755
--- a/test/bin/getopts_long-with_extdebug-silent
+++ b/test/bin/getopts_long-with_extdebug-silent
@@ -58,23 +58,17 @@ variables() {
     getopts_function -vuser_val1 --variable=user_val2 -- user_arg
 }
 
-disable_extdebug='false'
-if ! shopt -q extdebug; then
-    disable_extdebug='true'
+(
     shopt -s extdebug
-fi
 
-: "${1:?Missing required argument -- function name}"
-function_name=${1}
-shift
+    : "${1:?Missing required argument -- function name}"
+    function_name=${1}
+    shift
 
-if declare -f "$function_name" > /dev/null; then
-    ${function_name} "$@"
-else
-    echo "Function not found -- ${function_name}"
-    exit 1
-fi
-
-if ${disable_extdebug}; then
-    shopt -u extdebug
-fi
+    if declare -f "$function_name" > /dev/null; then
+        ${function_name} "$@"
+    else
+        echo "Function not found -- ${function_name}"
+        exit 1
+    fi
+)
diff --git a/test/bin/getopts_long-with_extdebug-verbose b/test/bin/getopts_long-with_extdebug-verbose
index 1bed59a..bc49db3 100755
--- a/test/bin/getopts_long-with_extdebug-verbose
+++ b/test/bin/getopts_long-with_extdebug-verbose
@@ -58,23 +58,17 @@ variables() {
     getopts_function -vuser_val1 --variable=user_val2 -- user_arg
 }
 
-disable_extdebug='false'
-if ! shopt -q extdebug; then
-    disable_extdebug='true'
+(
     shopt -s extdebug
-fi
 
-: "${1:?Missing required parameter -- function name}"
-function_name=${1}
-shift
+    : "${1:?Missing required parameter -- function name}"
+    function_name=${1}
+    shift
 
-if declare -f "$function_name" > /dev/null; then
-    ${function_name} "$@"
-else
-    echo "Function not found -- ${function_name}"
-    exit 1
-fi
-
-if ${disable_extdebug}; then
-    shopt -u extdebug
-fi
+    if declare -f "$function_name" > /dev/null; then
+        ${function_name} "$@"
+    else
+        echo "Function not found -- ${function_name}"
+        exit 1
+    fi
+)
diff --git a/test/bin/getopts_long-without_extdebug-silent b/test/bin/getopts_long-without_extdebug-silent
index 2daa2b5..57767a8 100755
--- a/test/bin/getopts_long-without_extdebug-silent
+++ b/test/bin/getopts_long-without_extdebug-silent
@@ -58,23 +58,17 @@ variables() {
     getopts_function -vuser_val1 --variable=user_val2 -- user_arg
 }
 
-enable_extdebug='false'
-if shopt -q extdebug; then
-    enable_extdebug='true'
+(
     shopt -u extdebug
-fi
 
-: "${1:?Missing required argument -- function name}"
-function_name=${1}
-shift
+    : "${1:?Missing required argument -- function name}"
+    function_name=${1}
+    shift
 
-if declare -f "$function_name" > /dev/null; then
-    ${function_name} "$@"
-else
-    echo "Function not found -- ${function_name}"
-    exit 1
-fi
-
-if ${enable_extdebug}; then
-    shopt -s extdebug
-fi
+    if declare -f "$function_name" > /dev/null; then
+        ${function_name} "$@"
+    else
+        echo "Function not found -- ${function_name}"
+        exit 1
+    fi
+)
diff --git a/test/bin/getopts_long-without_extdebug-verbose b/test/bin/getopts_long-without_extdebug-verbose
index 7f07ef3..3d3b3fb 100755
--- a/test/bin/getopts_long-without_extdebug-verbose
+++ b/test/bin/getopts_long-without_extdebug-verbose
@@ -58,23 +58,17 @@ variables() {
     getopts_function -vuser_val1 --variable=user_val2 -- user_arg
 }
 
-enable_extdebug='false'
-if shopt -q extdebug; then
-    enable_extdebug='true'
+(
     shopt -u extdebug
-fi
 
-: "${1:?Missing required parameter -- function name}"
-function_name=${1}
-shift
+    : "${1:?Missing required parameter -- function name}"
+    function_name=${1}
+    shift
 
-if declare -f "$function_name" > /dev/null; then
-    ${function_name} "$@"
-else
-    echo "Function not found -- ${function_name}"
-    exit 1
-fi
-
-if ${enable_extdebug}; then
-    shopt -s extdebug
-fi
+    if declare -f "$function_name" > /dev/null; then
+        ${function_name} "$@"
+    else
+        echo "Function not found -- ${function_name}"
+        exit 1
+    fi
+)