diff --git a/news/13555.bugfix.rst b/news/13555.bugfix.rst
new file mode 100644
index 00000000000..d0694f610c1
--- /dev/null
+++ b/news/13555.bugfix.rst
@@ -0,0 +1 @@
+Fix bash completion when the ``$IFS`` variable has been modified from its default.
diff --git a/src/pip/_internal/commands/completion.py b/src/pip/_internal/commands/completion.py
index 6d9597bdea0..7ba205d7263 100644
--- a/src/pip/_internal/commands/completion.py
+++ b/src/pip/_internal/commands/completion.py
@@ -14,9 +14,10 @@
     "bash": """
         _pip_completion()
         {{
+            local IFS=$' \\t\\n'
             COMPREPLY=( $( COMP_WORDS="${{COMP_WORDS[*]}}" \\
                            COMP_CWORD=$COMP_CWORD \\
-                           PIP_AUTO_COMPLETE=1 $1 2>/dev/null ) )
+                           PIP_AUTO_COMPLETE=1 "$1" 2>/dev/null ) )
         }}
         complete -o default -F _pip_completion {prog}
     """,
diff --git a/tests/functional/test_completion.py b/tests/functional/test_completion.py
index f0396aa0c68..01a8d819c58 100644
--- a/tests/functional/test_completion.py
+++ b/tests/functional/test_completion.py
@@ -15,9 +15,10 @@
         """\
 _pip_completion()
 {
+    local IFS=$' \\t\\n'
     COMPREPLY=( $( COMP_WORDS="${COMP_WORDS[*]}" \\
                    COMP_CWORD=$COMP_CWORD \\
-                   PIP_AUTO_COMPLETE=1 $1 2>/dev/null ) )
+                   PIP_AUTO_COMPLETE=1 "$1" 2>/dev/null ) )
 }
 complete -o default -F _pip_completion pip""",
     ),