diff --git a/lib/getopts_long.bash b/lib/getopts_long.bash
index b99ae04..9e0f469 100644
--- a/lib/getopts_long.bash
+++ b/lib/getopts_long.bash
@@ -20,7 +20,17 @@ getopts_long() {
     builtin getopts "${optspec_short}" "${optvar}" "${@}" || return 1
     [[ "${!optvar}" == '-' ]] || return 0
 
-    printf -v "${optvar}" "%s" "${OPTARG%%=*}"
+    if [[ "${OPTARG}" == *=* ]]; then
+        printf -v "${optvar}" "%s" "${OPTARG%%=*}"
+    else
+        for optspec in $(echo "${optspec_long}" | tr ' ' '\n' | sort -ur); do
+            if [[ "${optspec}" == *: && "${OPTARG}" == "${optspec%?}"* ]]; then
+                printf -v "${optvar}" "%s" "${optspec%?}"
+                break
+            fi
+        done
+        [[ "${!optvar}" == '-' ]] && printf -v "${optvar}" "%s" "${OPTARG}"
+    fi
 
     if [[ "${optspec_long}" =~ (^|[[:space:]])${!optvar}:([[:space:]]|$) ]]; then
         OPTARG="${OPTARG#"${!optvar}"}"
diff --git a/test/bats/github_15.bats b/test/bats/github_15.bats
new file mode 100644
index 0000000..11aa1f5
--- /dev/null
+++ b/test/bats/github_15.bats
@@ -0,0 +1,22 @@
+#!/usr/bin/env bats
+
+load ../test_helper
+
+@test "${FEATURE}: short option, silent" {
+    compare '-o-- user_arg' \
+            '-o-- user_arg'
+}
+@test "${FEATURE}: short option, verbose" {
+    compare '-o-- user_arg' \
+            '-o-- user_arg'
+}
+
+@test "${FEATURE}: long option, silent" {
+    compare '-o-- user_arg' \
+            '--option-- user_arg'
+}
+
+@test "${FEATURE}: long option, verbose" {
+    compare '-o-- user_arg' \
+            '--option-- user_arg'
+}
diff --git a/test/bats/option_supplied.bats b/test/bats/option_supplied.bats
index b5cda42..658329f 100644
--- a/test/bats/option_supplied.bats
+++ b/test/bats/option_supplied.bats
@@ -182,3 +182,24 @@ load ../test_helper
     compare '-o =user_val' \
             '--option =user_val'
 }
+
+# option with an adjoined value
+
+@test "${FEATURE}: short option, adjoined value, silent" {
+    compare '-ouser_val' \
+            '-ouser_val'
+}
+@test "${FEATURE}: short option, adjoined value, verbose" {
+    compare '-ouser_val' \
+            '-ouser_val'
+}
+
+@test "${FEATURE}: long option, adjoined value, silent" {
+    compare '-ouser_val' \
+            '--optionuser_val'
+}
+
+@test "${FEATURE}: long option, adjoined value, verbose" {
+    compare '-ouser_val' \
+            '--optionuser_val'
+}