diff --git a/src/policy/policy.h b/src/policy/policy.h
--- a/src/policy/policy.h
+++ b/src/policy/policy.h
@@ -94,7 +94,8 @@
     SCRIPT_VERIFY_SIGPUSHONLY | SCRIPT_VERIFY_MINIMALDATA |
     SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS | SCRIPT_VERIFY_CLEANSTACK |
     SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY | SCRIPT_VERIFY_CHECKSEQUENCEVERIFY |
-    SCRIPT_VERIFY_CHECKDATASIG_SIGOPS | SCRIPT_DISALLOW_SEGWIT_RECOVERY;
+    SCRIPT_VERIFY_CHECKDATASIG_SIGOPS | SCRIPT_DISALLOW_SEGWIT_RECOVERY |
+    SCRIPT_VERIFY_INPUT_SIGCHECKS;
 
 /**
  * For convenience, standard but not mandatory verify flags.
diff --git a/src/validation.cpp b/src/validation.cpp
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -477,6 +477,10 @@
                                        const CBlockIndex *pindexTip) {
     uint32_t flags = STANDARD_SCRIPT_VERIFY_FLAGS;
 
+    // Disable input sigchecks limit for mempool admission, prior to its
+    // proper activation.
+    flags &= ~SCRIPT_VERIFY_INPUT_SIGCHECKS;
+
     // We make sure this node will have replay protection during the next hard
     // fork.
     if (IsReplayProtectionEnabled(params, pindexTip)) {
diff --git a/test/functional/abc-wallet-standardness.py b/test/functional/abc-wallet-standardness.py
--- a/test/functional/abc-wallet-standardness.py
+++ b/test/functional/abc-wallet-standardness.py
@@ -166,9 +166,14 @@
         fund_and_test_wallet(
             CScript([b'\x01', pubkey, OP_1, OP_CHECKMULTISIG]), False, False,
             sign_error='Data push larger than necessary')
-        # Note: 1-of-5 is nonstandard to fund but standard to spend.
+        # Note: 1-of-5 is nonstandard to fund yet is standard to spend. However,
+        # trying to spend it with our wallet in particular will generate
+        # too-dense sigchecks since our wallet currently only signs with ECDSA
+        # (Schnorr would not have this issue).
         fund_and_test_wallet(
-            CScript([OP_1, pubkey, pubkey, pubkey, pubkey, pubkey, OP_5, OP_CHECKMULTISIG]), False, False)
+            CScript([OP_1, pubkey, pubkey, pubkey, pubkey, pubkey,
+                     OP_5, OP_CHECKMULTISIG]), False, False,
+            sign_error='Input SigChecks limit exceeded')
         fund_and_test_wallet(
             CScript([OP_1, pubkey, pubkey, pubkey, OP_PUSHDATA1,
                      pubkey, pubkey, OP_5, OP_CHECKMULTISIG]), False, False,