diff --git a/crypto/dsa/dsa_test.cc b/crypto/dsa/dsa_test.cc
index 4682131..cee783d 100644
--- a/crypto/dsa/dsa_test.cc
+++ b/crypto/dsa/dsa_test.cc
@@ -243,7 +243,7 @@
     fprintf(out, "%02X%02X%02X%02X ", seed[i], seed[i + 1], seed[i + 2],
             seed[i + 3]);
   }
-  fprintf(out, "\ncounter=%d h=%ld\n", counter, h);
+  fprintf(out, "\ncounter=%d h=%lu\n", counter, h);
 
   if (counter != 105) {
     fprintf(stderr, "counter should be 105\n");
diff --git a/crypto/evp/print.c b/crypto/evp/print.c
index 3621d5f..0f4b65e 100644
--- a/crypto/evp/print.c
+++ b/crypto/evp/print.c
@@ -253,7 +253,7 @@
 
   if (priv_key) {
     if (!BIO_indent(bp, off, 128) ||
-        BIO_printf(bp, "%s: (%d bit)\n", ktype, BN_num_bits(x->p)) <= 0) {
+        BIO_printf(bp, "%s: (%u bit)\n", ktype, BN_num_bits(x->p)) <= 0) {
       goto err;
     }
   }
@@ -368,7 +368,7 @@
   }
   order = BN_new();
   if (order == NULL || !EC_GROUP_get_order(group, order, NULL) ||
-      BIO_printf(bp, "%s: (%d bit)\n", ecstr, BN_num_bits(order)) <= 0) {
+      BIO_printf(bp, "%s: (%u bit)\n", ecstr, BN_num_bits(order)) <= 0) {
     goto err;
   }
 
diff --git a/crypto/fipsmodule/rand/urandom_test.cc b/crypto/fipsmodule/rand/urandom_test.cc
index b9e9007..0a1d753 100644
--- a/crypto/fipsmodule/rand/urandom_test.cc
+++ b/crypto/fipsmodule/rand/urandom_test.cc
@@ -91,7 +91,7 @@
 
     switch (type) {
       case Syscall::kGetRandom:
-        snprintf(buf, sizeof(buf), "getrandom(_, %zu, %d)", length, flags);
+        snprintf(buf, sizeof(buf), "getrandom(_, %zu, %u)", length, flags);
         break;
 
       case Syscall::kOpen:
diff --git a/crypto/x509v3/v3_alt.c b/crypto/x509v3/v3_alt.c
index ce1c6e5..eb9c975 100644
--- a/crypto/x509v3/v3_alt.c
+++ b/crypto/x509v3/v3_alt.c
@@ -172,12 +172,13 @@
     case GEN_IPADD:
         p = gen->d.ip->data;
         if (gen->d.ip->length == 4)
-            BIO_snprintf(oline, sizeof oline,
+            BIO_snprintf(oline, sizeof(oline),
                          "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
         else if (gen->d.ip->length == 16) {
             oline[0] = 0;
             for (i = 0; i < 8; i++) {
-                BIO_snprintf(htmp, sizeof htmp, "%X", p[0] << 8 | p[1]);
+                uint16_t v = ((uint16_t)p[0] << 8) | p[1];
+                BIO_snprintf(htmp, sizeof(htmp), "%X", v);
                 p += 2;
                 OPENSSL_strlcat(oline, htmp, sizeof(oline));
                 if (i != 7)
@@ -246,7 +247,8 @@
         else if (gen->d.ip->length == 16) {
             BIO_printf(out, "IP Address");
             for (i = 0; i < 8; i++) {
-                BIO_printf(out, ":%X", p[0] << 8 | p[1]);
+                uint16_t v = ((uint16_t)p[0] << 8) | p[1];
+                BIO_printf(out, ":%X", v);
                 p += 2;
             }
             BIO_puts(out, "\n");
diff --git a/crypto/x509v3/v3_ncons.c b/crypto/x509v3/v3_ncons.c
index 739a59e..f58873e 100644
--- a/crypto/x509v3/v3_ncons.c
+++ b/crypto/x509v3/v3_ncons.c
@@ -203,7 +203,8 @@
                    p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
     } else if (len == 32) {
         for (i = 0; i < 16; i++) {
-            BIO_printf(bp, "%X", p[0] << 8 | p[1]);
+            uint16_t v = ((uint16_t)p[0] << 8) | p[1];
+            BIO_printf(bp, "%X", v);
             p += 2;
             if (i == 7)
                 BIO_puts(bp, "/");
diff --git a/ssl/ssl_privkey.cc b/ssl/ssl_privkey.cc
index 8462ebf..41a13a2 100644
--- a/ssl/ssl_privkey.cc
+++ b/ssl/ssl_privkey.cc
@@ -663,7 +663,7 @@
 
   // Note that the loop runs to len+1, i.e. it'll process the terminating NUL.
   for (size_t offset = 0; offset < len+1; offset++) {
-    const char c = str[offset];
+    const unsigned char c = str[offset];
 
     switch (c) {
       case '+':
diff --git a/ssl/ssl_test.cc b/ssl/ssl_test.cc
index d0bd680..3286081 100644
--- a/ssl/ssl_test.cc
+++ b/ssl/ssl_test.cc
@@ -4694,7 +4694,7 @@
     }
   }
   char retry_count[256];
-  snprintf(retry_count, sizeof(retry_count), "%d", std::get<1>(params.param));
+  snprintf(retry_count, sizeof(retry_count), "%u", std::get<1>(params.param));
   ret += "_";
   ret += retry_count;
   ret += "Retries_";
diff --git a/ssl/test/handshake_util.cc b/ssl/test/handshake_util.cc
index b999831..6516547 100644
--- a/ssl/test/handshake_util.cc
+++ b/ssl/test/handshake_util.cc
@@ -255,7 +255,7 @@
           return false;
         }
         if (bytes_written != bytes_read) {
-          fprintf(stderr, "short write (%zu of %d bytes)\n", bytes_written,
+          fprintf(stderr, "short write (%zd of %d bytes)\n", bytes_written,
                   bytes_read);
           return false;
         }
diff --git a/ssl/test/test_config.cc b/ssl/test/test_config.cc
index 7d1cefa..16cb971 100644
--- a/ssl/test/test_config.cc
+++ b/ssl/test/test_config.cc
@@ -1047,17 +1047,16 @@
     const size_t num_received = sk_X509_NAME_num(received);
 
     if (num_received != num_expected) {
-      fprintf(stderr, "expected %u names in CertificateRequest but got %u.\n",
-              static_cast<unsigned>(num_expected),
-              static_cast<unsigned>(num_received));
+      fprintf(stderr, "expected %zu names in CertificateRequest but got %zu.\n",
+              num_expected, num_received);
       return false;
     }
 
     for (size_t i = 0; i < num_received; i++) {
       if (X509_NAME_cmp(sk_X509_NAME_value(received, i),
                         sk_X509_NAME_value(expected.get(), i)) != 0) {
-        fprintf(stderr, "names in CertificateRequest differ at index #%d.\n",
-                static_cast<unsigned>(i));
+        fprintf(stderr, "names in CertificateRequest differ at index #%zu.\n",
+                i);
         return false;
       }
     }
diff --git a/tool/transport_common.cc b/tool/transport_common.cc
index cba3c7b..991c808 100644
--- a/tool/transport_common.cc
+++ b/tool/transport_common.cc
@@ -306,13 +306,13 @@
   const uint8_t *next_proto;
   unsigned next_proto_len;
   SSL_get0_next_proto_negotiated(ssl, &next_proto, &next_proto_len);
-  BIO_printf(bio, "  Next protocol negotiated: %.*s\n", next_proto_len,
-             next_proto);
+  BIO_printf(bio, "  Next protocol negotiated: %.*s\n",
+             static_cast<int>(next_proto_len), next_proto);
 
   const uint8_t *alpn;
   unsigned alpn_len;
   SSL_get0_alpn_selected(ssl, &alpn, &alpn_len);
-  BIO_printf(bio, "  ALPN protocol: %.*s\n", alpn_len, alpn);
+  BIO_printf(bio, "  ALPN protocol: %.*s\n", static_cast<int>(alpn_len), alpn);
 
   const char *host_name = SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name);
   if (host_name != nullptr && SSL_is_server(ssl)) {