diff --git a/src/CLI.cpp b/src/CLI.cpp
index b188abe39..036345e5e 100644
--- a/src/CLI.cpp
+++ b/src/CLI.cpp
@@ -443,7 +443,7 @@ void CLI::analyze (bool parse /* = true */, bool strict /* = false */)
   // For propagation.
   _strict = strict;
 
-  for (int i = 0; i < _original_args.size (); ++i)
+  for (unsigned int i = 0; i < _original_args.size (); ++i)
   {
     std::string raw = _original_args[i];
     A a ("arg", raw);
@@ -2362,7 +2362,7 @@ bool CLI::isName (const std::string& raw) const
 {
   if (raw != "")
   {
-    for (int i = 0; i < raw.length (); ++i)
+    for (unsigned int i = 0; i < raw.length (); ++i)
     {
       if (i == 0 && ! Lexer::isIdentifierStart (raw[i]))
         return false;
diff --git a/src/Duration.cpp b/src/Duration.cpp
index c0b24501b..e3d3ea3ae 100644
--- a/src/Duration.cpp
+++ b/src/Duration.cpp
@@ -304,7 +304,7 @@ bool Duration::parse (const std::string& input, std::string::size_type& start)
   // Static and so preserved between calls.
   static std::vector <std::string> units;
   if (units.size () == 0)
-    for (int i = 0; i < NUM_DURATIONS; i++)
+    for (unsigned int i = 0; i < NUM_DURATIONS; i++)
       units.push_back (durations[i].unit);
 
   std::string number;
@@ -319,7 +319,7 @@ bool Duration::parse (const std::string& input, std::string::size_type& start)
 
       // Linear lookup - should be logarithmic.
       double seconds = 1;
-      for (int i = 0; i < NUM_DURATIONS; i++)
+      for (unsigned int i = 0; i < NUM_DURATIONS; i++)
       {
         if (durations[i].unit == unit &&
             durations[i].standalone == true)
@@ -344,7 +344,7 @@ bool Duration::parse (const std::string& input, std::string::size_type& start)
 
         // Linear lookup - should be logarithmic.
         double seconds = 1;
-        for (int i = 0; i < NUM_DURATIONS; i++)
+        for (unsigned int i = 0; i < NUM_DURATIONS; i++)
         {
           if (durations[i].unit == unit)
           {
diff --git a/src/Eval.cpp b/src/Eval.cpp
index 7319b75f1..dbbd8d9fe 100644
--- a/src/Eval.cpp
+++ b/src/Eval.cpp
@@ -446,7 +446,7 @@ void Eval::evaluatePostfixStack (
 void Eval::infixParse (
   std::vector <std::pair <std::string, Lexer::Type> >& infix) const
 {
-  int i = 0;
+  unsigned int i = 0;
   parseLogical (infix, i);
 }
 
@@ -454,7 +454,7 @@ void Eval::infixParse (
 // Logical     --> Regex {( "and" | "or" | "xor" ) Regex}
 bool Eval::parseLogical (
   std::vector <std::pair <std::string, Lexer::Type> >& infix,
-  int &i) const
+  unsigned int &i) const
 {
   if (i < infix.size () &&
       parseRegex (infix, i))
@@ -480,7 +480,7 @@ bool Eval::parseLogical (
 // Regex       --> Equality {( "~" | "!~" ) Equality}
 bool Eval::parseRegex (
   std::vector <std::pair <std::string, Lexer::Type> >& infix,
-  int &i) const
+  unsigned int &i) const
 {
   if (i < infix.size () &&
       parseEquality (infix, i))
@@ -505,7 +505,7 @@ bool Eval::parseRegex (
 // Equality    --> Comparative {( "==" | "=" | "!==" | "!=" ) Comparative}
 bool Eval::parseEquality (
   std::vector <std::pair <std::string, Lexer::Type> >& infix,
-  int &i) const
+  unsigned int &i) const
 {
   if (i < infix.size () &&
       parseComparative (infix, i))
@@ -532,7 +532,7 @@ bool Eval::parseEquality (
 // Comparative --> Arithmetic {( "<=" | "<" | ">=" | ">" ) Arithmetic}
 bool Eval::parseComparative (
   std::vector <std::pair <std::string, Lexer::Type> >& infix,
-  int &i) const
+  unsigned int &i) const
 {
   if (i < infix.size () &&
       parseArithmetic (infix, i))
@@ -559,7 +559,7 @@ bool Eval::parseComparative (
 // Arithmetic  --> Geometric {( "+" | "-" ) Geometric}
 bool Eval::parseArithmetic (
   std::vector <std::pair <std::string, Lexer::Type> >& infix,
-  int &i) const
+  unsigned int &i) const
 {
   if (i < infix.size () &&
       parseGeometric (infix, i))
@@ -584,7 +584,7 @@ bool Eval::parseArithmetic (
 // Geometric   --> Tag {( "*" | "/" | "%" ) Tag}
 bool Eval::parseGeometric (
   std::vector <std::pair <std::string, Lexer::Type> >& infix,
-  int &i) const
+  unsigned int &i) const
 {
   if (i < infix.size () &&
       parseTag (infix, i))
@@ -610,7 +610,7 @@ bool Eval::parseGeometric (
 // Tag         --> Unary {( "_hastag_" | "_notag_" ) Unary}
 bool Eval::parseTag (
   std::vector <std::pair <std::string, Lexer::Type> >& infix,
-  int &i) const
+  unsigned int &i) const
 {
   if (i < infix.size () &&
       parseUnary (infix, i))
@@ -635,7 +635,7 @@ bool Eval::parseTag (
 // Unary       --> [( "-" | "+" | "!" )] Exponent
 bool Eval::parseUnary (
   std::vector <std::pair <std::string, Lexer::Type> >& infix,
-  int &i) const
+  unsigned int &i) const
 {
   if (i < infix.size ())
   {
@@ -662,7 +662,7 @@ bool Eval::parseUnary (
 // Exponent    --> Primitive ["^" Primitive]
 bool Eval::parseExponent (
   std::vector <std::pair <std::string, Lexer::Type> >& infix,
-  int &i) const
+  unsigned int& i) const
 {
   if (i < infix.size () &&
       parsePrimitive (infix, i))
@@ -686,7 +686,7 @@ bool Eval::parseExponent (
 // Primitive   --> "(" Logical ")" | Variant
 bool Eval::parsePrimitive (
   std::vector <std::pair <std::string, Lexer::Type> >& infix,
-  int &i) const
+  unsigned int &i) const
 {
   if (i < infix.size ())
   {
@@ -781,7 +781,7 @@ void Eval::infixToPostfix (
 
   // Operator characteristics.
   char type;
-  int precedence;
+  unsigned int precedence;
   char associativity;
 
   std::vector <std::pair <std::string, Lexer::Type> >::iterator token;
@@ -811,7 +811,7 @@ void Eval::infixToPostfix (
              identifyOperator (token->first, type, precedence, associativity))
     {
       char type2;
-      int precedence2;
+      unsigned int precedence2;
       char associativity2;
       while (op_stack.size () > 0 &&
              identifyOperator (op_stack.back ().first, type2, precedence2, associativity2) &&
@@ -847,7 +847,7 @@ void Eval::infixToPostfix (
 bool Eval::identifyOperator (
   const std::string& op,
   char& type,
-  int& precedence,
+  unsigned int& precedence,
   char& associativity) const
 {
   for (unsigned int i = 0; i < NUM_OPERATORS; ++i)
diff --git a/src/Eval.h b/src/Eval.h
index b0062814b..16765ff4d 100644
--- a/src/Eval.h
+++ b/src/Eval.h
@@ -56,17 +56,17 @@ private:
   void evaluatePostfixStack (const std::vector <std::pair <std::string, Lexer::Type> >&, Variant&) const;
   void infixToPostfix (std::vector <std::pair <std::string, Lexer::Type> >&) const;
   void infixParse (std::vector <std::pair <std::string, Lexer::Type> >&) const;
-  bool parseLogical (std::vector <std::pair <std::string, Lexer::Type> >&, int &) const;
-  bool parseRegex (std::vector <std::pair <std::string, Lexer::Type> >&, int &) const;
-  bool parseEquality (std::vector <std::pair <std::string, Lexer::Type> >&, int &) const;
-  bool parseComparative (std::vector <std::pair <std::string, Lexer::Type> >&, int &) const;
-  bool parseArithmetic (std::vector <std::pair <std::string, Lexer::Type> >&, int &) const;
-  bool parseGeometric (std::vector <std::pair <std::string, Lexer::Type> >&, int &) const;
-  bool parseTag (std::vector <std::pair <std::string, Lexer::Type> >&, int &) const;
-  bool parseUnary (std::vector <std::pair <std::string, Lexer::Type> >&, int &) const;
-  bool parseExponent (std::vector <std::pair <std::string, Lexer::Type> >&, int &) const;
-  bool parsePrimitive (std::vector <std::pair <std::string, Lexer::Type> >&, int &) const;
-  bool identifyOperator (const std::string&, char&, int&, char&) const;
+  bool parseLogical (std::vector <std::pair <std::string, Lexer::Type> >&, unsigned int &) const;
+  bool parseRegex (std::vector <std::pair <std::string, Lexer::Type> >&, unsigned int &) const;
+  bool parseEquality (std::vector <std::pair <std::string, Lexer::Type> >&, unsigned int &) const;
+  bool parseComparative (std::vector <std::pair <std::string, Lexer::Type> >&, unsigned int &) const;
+  bool parseArithmetic (std::vector <std::pair <std::string, Lexer::Type> >&, unsigned int &) const;
+  bool parseGeometric (std::vector <std::pair <std::string, Lexer::Type> >&, unsigned int &) const;
+  bool parseTag (std::vector <std::pair <std::string, Lexer::Type> >&, unsigned int &) const;
+  bool parseUnary (std::vector <std::pair <std::string, Lexer::Type> >&, unsigned int &) const;
+  bool parseExponent (std::vector <std::pair <std::string, Lexer::Type> >&, unsigned int &) const;
+  bool parsePrimitive (std::vector <std::pair <std::string, Lexer::Type> >&, unsigned int &) const;
+  bool identifyOperator (const std::string&, char&, unsigned int&, char&) const;
 
   std::string dump (std::vector <std::pair <std::string, Lexer::Type> >&) const;
 
diff --git a/src/Hooks.cpp b/src/Hooks.cpp
index cad0f0c7d..eaf171543 100644
--- a/src/Hooks.cpp
+++ b/src/Hooks.cpp
@@ -466,7 +466,7 @@ void Hooks::assertValidJSON (const std::vector <std::string>& input) const
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-void Hooks::assertNTasks (const std::vector <std::string>& input, int n) const
+void Hooks::assertNTasks (const std::vector <std::string>& input, unsigned int n) const
 {
   if (input.size () != n)
   {
diff --git a/src/Hooks.h b/src/Hooks.h
index 37807824e..1bb33a2f7 100644
--- a/src/Hooks.h
+++ b/src/Hooks.h
@@ -54,7 +54,7 @@ private:
   void separateOutput (const std::vector <std::string>&, std::vector <std::string>&, std::vector <std::string>&) const;
   bool isJSON (const std::string&) const;
   void assertValidJSON (const std::vector <std::string>&) const;
-  void assertNTasks (const std::vector <std::string>&, int) const;
+  void assertNTasks (const std::vector <std::string>&, unsigned int) const;
   void assertSameTask (const std::vector <std::string>&, const Task&) const;
   void assertFeedback (const std::vector <std::string>&) const;
   int callHookScript (const std::string&, const std::vector <std::string>&, std::vector <std::string>&);
diff --git a/src/TDB2.cpp b/src/TDB2.cpp
index abcafd3a8..7c25747d0 100644
--- a/src/TDB2.cpp
+++ b/src/TDB2.cpp
@@ -102,7 +102,7 @@ bool TF2::get (int id, Task& task)
   // pending.data file, the task in question cannot appear earlier than line
   // (id - 1) in the file.  It can, however, appear significantly later because
   // it is not known how recent a GC operation was run.
-  for (int i = id - 1; i < _tasks.size (); ++i)
+  for (unsigned int i = id - 1; i < _tasks.size (); ++i)
   {
     if (_tasks[i].id == id)
     {
diff --git a/src/text.cpp b/src/text.cpp
index 857d0d259..b554e1831 100644
--- a/src/text.cpp
+++ b/src/text.cpp
@@ -956,7 +956,7 @@ std::string rightJustify (const int input, const int width)
 std::string rightJustify (const std::string& input, const int width)
 {
   unsigned int len = utf8_text_width (input);
-  return ((width > len)
+  return (((unsigned int) width > len)
            ? std::string (width - len, ' ')
            : "")
          + input;