diff --git a/internal/devbox/shell_test.go b/internal/devbox/shell_test.go
index 952286bfacb..ee361a14564 100644
--- a/internal/devbox/shell_test.go
+++ b/internal/devbox/shell_test.go
@@ -8,6 +8,7 @@ import (
 	"flag"
 	"io/fs"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"regexp"
 	"strings"
@@ -487,3 +488,62 @@ func TestWriteDevboxShellrcWithZDOTDIR(t *testing.T) {
 		t.Error("Expected shellrc to source the custom .zshrc file")
 	}
 }
+
+// TestWriteDevboxShellrcZDOTDIRWithSpaces guards against a regression where the
+// `[ -f <path> ]` guard around sourcing the user's shellrc was unquoted. When
+// ZDOTDIR contains spaces (e.g. ".../Application Support/..."), the unquoted
+// path expands to multiple words and `[` fails with "too many arguments", so
+// the user's real shellrc never gets sourced.
+func TestWriteDevboxShellrcZDOTDIRWithSpaces(t *testing.T) {
+	// A ZDOTDIR with a space, like the one some terminal integrations inject.
+	zdotdir := filepath.Join(t.TempDir(), "Application Support", "zsh")
+	if err := os.MkdirAll(zdotdir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	t.Setenv("ZDOTDIR", zdotdir)
+
+	zshrcPath := filepath.Join(zdotdir, ".zshrc")
+	if err := os.WriteFile(zshrcPath, []byte("# user zshrc"), 0o644); err != nil {
+		t.Fatalf("Failed to create test .zshrc: %v", err)
+	}
+
+	shell := initShellBinaryFields("/usr/bin/zsh")
+	shell.devbox = &Devbox{projectDir: "/test/project"}
+	shell.projectDir = "/test/project"
+
+	shellrcPath, err := shell.writeDevboxShellrc()
+	if err != nil {
+		t.Fatalf("Failed to write devbox shellrc: %v", err)
+	}
+	content, err := os.ReadFile(shellrcPath)
+	if err != nil {
+		t.Fatalf("Failed to read generated shellrc: %v", err)
+	}
+	contentStr := string(content)
+
+	// The guard must quote the path so the space doesn't split into words.
+	wantGuard := `if [ -f "` + zshrcPath + `" ]; then`
+	if !strings.Contains(contentStr, wantGuard) {
+		t.Errorf("expected quoted guard %q in generated shellrc:\n%s", wantGuard, contentStr)
+	}
+
+	// Run the actual generated guard line through /bin/sh to prove it doesn't
+	// error with "too many arguments" on a space-containing path.
+	var guardLine string
+	for _, line := range strings.Split(contentStr, "\n") {
+		if strings.HasPrefix(strings.TrimSpace(line), "if [ -f ") {
+			guardLine = strings.TrimSpace(line) + " echo sourced; fi"
+			break
+		}
+	}
+	if guardLine == "" {
+		t.Fatalf("could not find guard line in generated shellrc:\n%s", contentStr)
+	}
+	out, err := exec.Command("/bin/sh", "-c", guardLine).CombinedOutput()
+	if err != nil {
+		t.Fatalf("guard line failed to execute (%v): %s\nline: %s", err, out, guardLine)
+	}
+	if strings.TrimSpace(string(out)) != "sourced" {
+		t.Errorf("guard line did not take the true branch; output: %q\nline: %s", out, guardLine)
+	}
+}
diff --git a/internal/devbox/shellrc.tmpl b/internal/devbox/shellrc.tmpl
index 037012a22c1..1ff790d496b 100644
--- a/internal/devbox/shellrc.tmpl
+++ b/internal/devbox/shellrc.tmpl
@@ -20,14 +20,14 @@ content readable.
 
 {{- if .OriginalInitPath -}}
 {{- if eq .ShellName "zsh" -}}
-if [ -f {{ .OriginalInitPath }} ]; then
+if [ -f "{{ .OriginalInitPath }}" ]; then
   local DEVBOX_ZDOTDIR="$ZDOTDIR"
   export ZDOTDIR="{{dirPath .OriginalInitPath}}"
   . "{{ .OriginalInitPath }}"
   export ZDOTDIR="$DEVBOX_ZDOTDIR"
 fi
 {{ else -}}
-if [ -f {{ .OriginalInitPath }} ]; then
+if [ -f "{{ .OriginalInitPath }}" ]; then
   . "{{ .OriginalInitPath }}"
 fi
 {{ end -}}
diff --git a/internal/devbox/testdata/shellrc/basic/shellrc.golden b/internal/devbox/testdata/shellrc/basic/shellrc.golden
index 45a901c3a5e..b22fbfb2a71 100644
--- a/internal/devbox/testdata/shellrc/basic/shellrc.golden
+++ b/internal/devbox/testdata/shellrc/basic/shellrc.golden
@@ -1,4 +1,4 @@
-if [ -f testdata/shellrc/basic/shellrc ]; then
+if [ -f "testdata/shellrc/basic/shellrc" ]; then
   . "testdata/shellrc/basic/shellrc"
 fi
 # Begin Devbox Post-init Hook
diff --git a/internal/devbox/testdata/shellrc/zsh_zdotdir/shellrc.golden b/internal/devbox/testdata/shellrc/zsh_zdotdir/shellrc.golden
index 19194369a52..bb23c48724c 100644
--- a/internal/devbox/testdata/shellrc/zsh_zdotdir/shellrc.golden
+++ b/internal/devbox/testdata/shellrc/zsh_zdotdir/shellrc.golden
@@ -1,4 +1,4 @@
-if [ -f testdata/shellrc/zsh_zdotdir/shellrc ]; then
+if [ -f "testdata/shellrc/zsh_zdotdir/shellrc" ]; then
   local DEVBOX_ZDOTDIR="$ZDOTDIR"
   export ZDOTDIR="testdata/shellrc/zsh_zdotdir"
   . "testdata/shellrc/zsh_zdotdir/shellrc"