diff --git a/agent/agent.h b/agent/agent.h
--- a/agent/agent.h
+++ b/agent/agent.h
@@ -116,6 +116,9 @@
   /* File name with a patternfile or NULL if not enabled.  */
   const char *check_passphrase_pattern;
 
+  /* Path to a external passphrase checker (NULL to disable). */
+  const char *passphrase_quality_checker;
+
   /* If not 0 the user is asked to change his passphrase after these
      number of days.  */
   unsigned int max_passphrase_days;
diff --git a/agent/call-pinentry.c b/agent/call-pinentry.c
--- a/agent/call-pinentry.c
+++ b/agent/call-pinentry.c
@@ -39,6 +39,7 @@
 #include <assuan.h>
 #include "../common/sysutils.h"
 #include "../common/i18n.h"
+#include "../common/exectool.h"
 
 #ifdef _POSIX_OPEN_MAX
 #define MAX_OPEN_FDS _POSIX_OPEN_MAX
@@ -779,6 +780,24 @@
   int length;
   const char *s;
 
+  if (opt.passphrase_quality_checker)
+    {
+      char *output;
+      long percent;
+
+      if (gnupg_exec_tool (opt.passphrase_quality_checker, NULL,
+                           pw, &output, NULL))
+        return 0;
+
+      percent = strtol (output, NULL, 10);
+      if (percent < 0)
+        percent = 0;
+      if (percent > 100)
+        percent = 100;
+
+      return percent;
+    }
+
   if (goodlength < 1)
     return 0;
 
diff --git a/agent/gpg-agent.c b/agent/gpg-agent.c
--- a/agent/gpg-agent.c
+++ b/agent/gpg-agent.c
@@ -110,6 +110,7 @@
   oMinPassphraseLen,
   oMinPassphraseNonalpha,
   oCheckPassphrasePattern,
+  oPassphraseChecker,
   oMaxPassphraseDays,
   oEnablePassphraseHistory,
   oEnableExtendedKeyFormat,
@@ -220,6 +221,7 @@
   ARGPARSE_s_s (oCheckPassphrasePattern,  "check-passphrase-pattern", "@"),
   ARGPARSE_s_u (oMaxPassphraseDays,       "max-passphrase-days", "@"),
   ARGPARSE_s_n (oEnablePassphraseHistory, "enable-passphrase-history", "@"),
+  ARGPARSE_s_s (oPassphraseChecker,       "passphrase-checker", "@"),
 
   ARGPARSE_s_n (oIgnoreCacheForSigning, "ignore-cache-for-signing",
                 /* */    N_("do not use the PIN cache when signing")),
@@ -807,6 +809,7 @@
       opt.min_passphrase_len = MIN_PASSPHRASE_LEN;
       opt.min_passphrase_nonalpha = MIN_PASSPHRASE_NONALPHA;
       opt.check_passphrase_pattern = NULL;
+      opt.passphrase_quality_checker = NULL;
       opt.max_passphrase_days = MAX_PASSPHRASE_DAYS;
       opt.enable_passphrase_history = 0;
       opt.enable_extended_key_format = 0;
@@ -875,6 +878,9 @@
     case oCheckPassphrasePattern:
       opt.check_passphrase_pattern = pargs->r.ret_str;
       break;
+    case oPassphraseChecker:
+      opt.passphrase_quality_checker = pargs->r.ret_str;
+      break;
     case oMaxPassphraseDays:
       opt.max_passphrase_days = pargs->r.ret_ulong;
       break;