diff --git a/src/backend/access/spgist/spgdoinsert.c b/src/backend/access/spgist/spgdoinsert.c
index 5ddb6672c5c8cb3877a47ca9952fae74b38704b7..98a7bea742ea87bb81611586df035a8d6c169ac2 100644
--- a/src/backend/access/spgist/spgdoinsert.c
+++ b/src/backend/access/spgist/spgdoinsert.c
@@ -818,7 +818,7 @@ doPickSplit(Relation index, SpGistState *state,
 
 	/*
 	 * We may not actually insert new tuple because another picksplit may be
-	 * necessary due to too large value, but we will try to to allocate enough
+	 * necessary due to too large value, but we will try to allocate enough
 	 * space to include it; and in any case it has to be included in the input
 	 * for the picksplit function.  So don't increment nToInsert yet.
 	 */
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index 2924d0ff65dcd4c2e994b78445cf24f737fd838e..845a839e67f27cda099f83437bdf76ec10d80f05 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -283,7 +283,7 @@ ResolveRecoveryConflictWithTablespace(Oid tsid)
 	VirtualTransactionId *temp_file_users;
 
 	/*
-	 * Standby users may be currently using this tablespace for for their
+	 * Standby users may be currently using this tablespace for their
 	 * temporary files. We only care about current users because
 	 * temp_tablespace parameter will just ignore tablespaces that no longer
 	 * exist.
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 51d623ff3e3ab83827389d78a839298c6bf3061f..6a745997c55b71ccdf0bf93fa9d5be297988d6ac 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -3021,7 +3021,7 @@ check_stack_depth(void)
 	long		stack_depth;
 
 	/*
-	 * Compute distance from reference point to to my local variables
+	 * Compute distance from reference point to my local variables
 	 */
 	stack_depth = (long) (stack_base_ptr - &stack_top_loc);
 
diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c
index 5723b9af4ed17af86ca1bfb00a7a238efff6454f..14bbdad93ba27a9d38c10fa13b1fbf502b06c8f0 100644
--- a/src/backend/utils/adt/numeric.c
+++ b/src/backend/utils/adt/numeric.c
@@ -3503,7 +3503,7 @@ get_str_from_var(NumericVar *var, int dscale)
 	/*
 	 * Allocate space for the result.
 	 *
-	 * i is set to to # of decimal digits before decimal point. dscale is the
+	 * i is set to the # of decimal digits before decimal point. dscale is the
 	 * # of decimal digits we will print after decimal point. We may generate
 	 * as many as DEC_DIGITS-1 excess digits at the end, and in addition we
 	 * need room for sign, decimal point, null terminator.
diff --git a/src/include/tsearch/dicts/regis.h b/src/include/tsearch/dicts/regis.h
index 34d15e06f37466e1f58f0341b477f5baafd8ec09..13dc5c28a160076906a9967b23fb0ba109e29c4e 100644
--- a/src/include/tsearch/dicts/regis.h
+++ b/src/include/tsearch/dicts/regis.h
@@ -2,7 +2,7 @@
  *
  * regis.h
  *
- * Declarations for for fast regex subset, used by ISpell
+ * Declarations for fast regex subset, used by ISpell
  *
  * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
  *