diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -859,8 +859,8 @@
   m4_ifdef(
     [PKG_CHECK_MODULES],
     [
-      PKG_CHECK_MODULES([SSL], [libssl],, [AC_MSG_ERROR(openssl  not found.)])
-      PKG_CHECK_MODULES([CRYPTO], [libcrypto],,[AC_MSG_ERROR(libcrypto  not found.)])
+      PKG_CHECK_MODULES([SSL], [libssl],, [AC_MSG_ERROR(openssl not found.)])
+      PKG_CHECK_MODULES([CRYPTO], [libcrypto],,[AC_MSG_ERROR(libcrypto not found.)])
       BITCOIN_QT_CHECK([PKG_CHECK_MODULES([PROTOBUF], [protobuf], [have_protobuf=yes], [BITCOIN_QT_FAIL(libprotobuf not found)])])
       if test x$use_qr != xno; then
         BITCOIN_QT_CHECK([PKG_CHECK_MODULES([QR], [libqrencode], [have_qrencode=yes], [have_qrencode=no])])
diff --git a/src/chainparams.cpp b/src/chainparams.cpp
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -164,7 +164,7 @@
 
         // Note that of those which support the service bits prefix, most only
         // support a subset of possible options. This is fine at runtime as
-        // we'll fall back to using them as a oneshot if they dont support the
+        // we'll fall back to using them as a oneshot if they don't support the
         // service bits we want, but we should get them updated to support all
         // service bits wanted by any release ASAP to avoid it where possible.
         // Bitcoin ABC seeder
diff --git a/src/protocol.h b/src/protocol.h
--- a/src/protocol.h
+++ b/src/protocol.h
@@ -341,7 +341,7 @@
  * Thus, generally, avoid calling with peerServices == NODE_NONE, unless
  * state-specific flags must absolutely be avoided. When called with
  * peerServices == NODE_NONE, the returned desirable service flags are
- * guaranteed to not change dependant on state - ie they are suitable for
+ * guaranteed to not change dependent on state - ie they are suitable for
  * use when describing peers which we know to be desirable, but for which
  * we do not have a confirmed set of service flags.
  *
diff --git a/src/streams.h b/src/streams.h
--- a/src/streams.h
+++ b/src/streams.h
@@ -68,7 +68,7 @@
      * @param[in]  nVersionIn Serialization Version (including any flags)
      * @param[in]  vchDataIn  Referenced byte vector to overwrite/append
      * @param[in]  nPosIn Starting position. Vector index where writes should
-     * start. The vector will initially grow as necessary to  max(index,
+     * start. The vector will initially grow as necessary to max(index,
      * vec.size()). So to append, use vec.size().
      */
     CVectorWriter(int nTypeIn, int nVersionIn, std::vector<uint8_t> &vchDataIn,
diff --git a/src/sync.cpp b/src/sync.cpp
--- a/src/sync.cpp
+++ b/src/sync.cpp
@@ -23,8 +23,8 @@
 //
 // Early deadlock detection.
 // Problem being solved:
-//    Thread 1 locks  A, then B, then C
-//    Thread 2 locks  D, then C, then A
+//    Thread 1 locks A, then B, then C
+//    Thread 2 locks D, then C, then A
 //     --> may result in deadlock between the two threads, depending on when
 //     they run.
 // Solution implemented here:
diff --git a/src/validation.cpp b/src/validation.cpp
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -2932,7 +2932,7 @@
         if (GetMainSignals().CallbacksPending() > 10) {
             // Block until the validation queue drains. This should largely
             // never happen in normal operation, however may happen during
-            // reindex, causing memory blowup  if we run too far ahead.
+            // reindex, causing memory blowup if we run too far ahead.
             SyncWithValidationInterfaceQueue();
         }
 
diff --git a/src/wallet/test/wallet_tests.cpp b/src/wallet/test/wallet_tests.cpp
--- a/src/wallet/test/wallet_tests.cpp
+++ b/src/wallet/test/wallet_tests.cpp
@@ -115,7 +115,7 @@
         BOOST_CHECK(!wallet.SelectCoinsMinConf(3 * CENT, 1, 6, 0, vCoins,
                                                setCoinsRet, nValueRet));
 
-        // we can make 3 cents of new  coins
+        // we can make 3 cents of new coins
         BOOST_CHECK(wallet.SelectCoinsMinConf(3 * CENT, 1, 1, 0, vCoins,
                                               setCoinsRet, nValueRet));
         BOOST_CHECK_EQUAL(nValueRet, 3 * CENT);
diff --git a/test/functional/test_framework/mininode.py b/test/functional/test_framework/mininode.py
--- a/test/functional/test_framework/mininode.py
+++ b/test/functional/test_framework/mininode.py
@@ -6,7 +6,7 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Bitcoin P2P network half-a-node.
 
-This python code was modified from ArtForz' public domain  half-a-node, as
+This python code was modified from ArtForz' public domain half-a-node, as
 found in the mini-node branch of http://github.com/jgarzik/pynode.
 
 P2PConnection: A low-level connection object to a node's P2P interface