diff --git a/src/core/core.c b/src/core/core.c
index 64e283e..95e74b1 100644
--- a/src/core/core.c
+++ b/src/core/core.c
@@ -7,6 +7,7 @@
 #include "core_string.c"
 #include "core_string16.c"
 #include "core_json.c"
+#include "core_csv.c"
 #include "core_log.c"
 #include "core_lexer.c"
 #include "core_type_info.c"
diff --git a/src/core/core.h b/src/core/core.h
index 775be24..2ef7edc 100644
--- a/src/core/core.h
+++ b/src/core/core.h
@@ -4,6 +4,7 @@
 #include "core_string.h"
 #include "core_string16.h"
 #include "core_json.h"
+#include "core_csv.h"
 #include "core_math.h"
 #include "core_type_info.h"
 #include "core_lexer.h"
diff --git a/src/core/core_csv.c b/src/core/core_csv.c
new file mode 100644
index 0000000..72f517e
--- /dev/null
+++ b/src/core/core_csv.c
@@ -0,0 +1,180 @@
+#include "core_csv.h"
+#include "core_log.h"
+
+typedef struct csv_field_node_t csv_field_node_t;
+struct csv_field_node_t {
+    csv_field_node_t *next;
+    s8_t field;
+};
+
+fn b32 csv_at_end(csv_parser_t *it) {
+    b32 result = it->at >= it->end;
+    return result;
+}
+
+fn b32 csv_starts_with(csv_parser_t *it, s8_t string) {
+    if (string.len == 0) return false;
+    if (it->end - it->at < string.len) return false;
+    b32 result = s8_are_equal(s8_make(it->at, string.len), string);
+    return result;
+}
+
+fn void csv_consume(csv_parser_t *it, i64 len) {
+    it->at += len;
+}
+
+fn i64 csv_line_end_len(csv_parser_t *it) {
+    i64 result = 0;
+    if (it->line_terminator.len) {
+        if (csv_starts_with(it, it->line_terminator)) result = it->line_terminator.len;
+    } else if (!csv_at_end(it)) {
+        if (it->at[0] == '\r' && it->end - it->at >= 2 && it->at[1] == '\n') result = 2;
+        else if (it->at[0] == '\n') result = 1;
+    }
+    return result;
+}
+
+fn void csv_errorf(csv_parser_t *it, const char *fmt, ...) {
+    if (it->has_error) return;
+    it->has_error = true;
+    it->is_valid = false;
+
+    va_list args;
+    va_start(args, fmt);
+    s8_t msg = s8_vfmt(it->arena, fmt, args);
+    va_end(args);
+
+    it->error = s8_printf(it->arena, "csv row %d: %S", it->row, msg);
+    errorf("%S", it->error);
+}
+
+fn void csv_sb_putc(sb8_t *sb, char c) {
+    char *p = ma_push_type(sb->arena, char);
+    *p = c;
+    sb8_append(sb, s8_make(p, 1));
+}
+
+fn s8_t csv_parse_field(csv_parser_t *it) {
+    if (!csv_at_end(it) && it->at[0] == '"') {
+        // Quoted field. The outer quotes are removed and doubled quotes are
+        // unescaped. Quoted fields may contain delimiters and line endings.
+        csv_consume(it, 1);
+        sb8_t sb = {.arena = it->arena};
+
+        for (;;) {
+            if (csv_at_end(it)) {
+                csv_errorf(it, "unterminated quoted field");
+                return s8_null;
+            }
+
+            if (it->at[0] == '"') {
+                csv_consume(it, 1);
+                if (!csv_at_end(it) && it->at[0] == '"') {
+                    csv_sb_putc(&sb, '"');
+                    csv_consume(it, 1);
+                    continue;
+                }
+                break;
+            }
+
+            csv_sb_putc(&sb, it->at[0]);
+            csv_consume(it, 1);
+        }
+
+        s8_t result = sb8_merge(it->arena, &sb);
+        return result;
+    }
+
+    // Unquoted field is a view into the input buffer.
+    char *first = it->at;
+    while (!csv_at_end(it) && !csv_starts_with(it, it->delimiter) && csv_line_end_len(it) == 0) {
+        csv_consume(it, 1);
+    }
+    s8_t result = s8_from_range(first, it->at);
+    return result;
+}
+
+fn void csv_clear_row(csv_parser_t *it) {
+    if (it->has_row_temp) {
+        ma_end_temp(it->row_temp);
+        it->has_row_temp = false;
+    }
+    it->data = NULL;
+    it->len = 0;
+}
+
+fn csv_parser_t csv_iter(ma_arena_t *arena, s8_t stream, csv_params_t params) {
+    assert(arena);
+    csv_parser_t result = {0};
+    result.arena = arena;
+    result.at = stream.str;
+    result.end = stream.str + stream.len;
+    result.delimiter = params.delimiter.len ? params.delimiter : s8(",");
+    result.line_terminator = params.line_terminator;
+    result.row = 0;
+
+    assert(result.delimiter.len > 0);
+    csv_advance(&result);
+    return result;
+}
+
+fn b32 csv_is_valid(csv_parser_t *it) {
+    b32 result = it->is_valid && !it->has_error;
+    return result;
+}
+
+fn void csv_advance(csv_parser_t *it) {
+    csv_clear_row(it);
+    if (it->has_error || csv_at_end(it)) {
+        it->is_valid = false;
+        return;
+    }
+
+    it->row += 1;
+    it->row_temp = ma_begin_temp(it->arena);
+    it->has_row_temp = true;
+
+    csv_field_node_t *first = NULL;
+    csv_field_node_t *last = NULL;
+    i32 count = 0;
+
+    for (;;) {
+        s8_t field = csv_parse_field(it);
+        if (it->has_error) return;
+
+        csv_field_node_t *node = ma_push_type(it->arena, csv_field_node_t);
+        node->field = field;
+        SLLQ_APPEND(first, last, node);
+        count += 1;
+
+        if (csv_starts_with(it, it->delimiter)) {
+            csv_consume(it, it->delimiter.len);
+            continue;
+        }
+
+        i64 line_end_len = csv_line_end_len(it);
+        if (line_end_len) {
+            csv_consume(it, line_end_len);
+            break;
+        }
+
+        if (csv_at_end(it)) break;
+
+        csv_errorf(it, "expected delimiter or line terminator");
+        return;
+    }
+
+    // Copy the scratch-like linked list representation into a tight row array.
+    it->data = ma_push_array(it->arena, s8_t, count);
+    it->len = count;
+    i32 idx = 0;
+    for (csv_field_node_t *node = first; node; node = node->next) {
+        it->data[idx++] = node->field;
+    }
+    it->is_valid = true;
+}
+
+fn void csv_end(csv_parser_t *it) {
+    csv_clear_row(it);
+    it->is_valid = false;
+}
diff --git a/src/core/core_csv.h b/src/core/core_csv.h
new file mode 100644
index 0000000..59c5367
--- /dev/null
+++ b/src/core/core_csv.h
@@ -0,0 +1,34 @@
+#pragma once
+#include "core_basic.h"
+#include "core_arena.h"
+#include "core_string.h"
+
+typedef struct csv_params_t csv_params_t;
+struct csv_params_t {
+    s8_t delimiter;       // defaults to ","
+    s8_t line_terminator; // defaults to accepting "\n" and "\r\n"
+};
+
+typedef struct csv_parser_t csv_parser_t;
+struct csv_parser_t {
+    ma_arena_t *arena;
+    ma_temp_t row_temp;
+    b32 has_row_temp;
+
+    char *at;
+    char *end;
+    s8_t delimiter;
+    s8_t line_terminator;
+
+    s8_t *data;
+    i32 len;
+    i32 row;
+    b32 is_valid;
+    b32 has_error;
+    s8_t error;
+};
+
+fn csv_parser_t csv_iter(ma_arena_t *arena, s8_t stream, csv_params_t params);
+fn b32          csv_is_valid(csv_parser_t *it);
+fn void         csv_advance(csv_parser_t *it);
+fn void         csv_end(csv_parser_t *it);
diff --git a/src/testing/testing_main.c b/src/testing/testing_main.c
index 233cd53..6aeb8ea 100644
--- a/src/testing/testing_main.c
+++ b/src/testing/testing_main.c
@@ -131,6 +131,62 @@ fn void test_json(void) {
     ma_destroy(arena);
 }
 
+fn void test_csv(void) {
+    ma_arena_t *arena = ma_create(ma_default_reserve_size);
+
+    s8_t stream = s8("name,age,note\nBob,32,hello\nAlice,27,\"hi, there\"\n\"Q\"\"uote\"\"\",,tail\n");
+    csv_params_t params = {0};
+
+    i32 row = 0;
+    for (csv_parser_t it = csv_iter(arena, stream, params); csv_is_valid(&it); csv_advance(&it)) {
+        if (row == 0) {
+            assert(it.len == 3);
+            assert(s8_are_equal(it.data[0], s8("name")));
+            assert(s8_are_equal(it.data[1], s8("age")));
+            assert(s8_are_equal(it.data[2], s8("note")));
+        } else if (row == 1) {
+            assert(it.len == 3);
+            assert(s8_are_equal(it.data[0], s8("Bob")));
+            assert(s8_are_equal(it.data[1], s8("32")));
+            assert(s8_are_equal(it.data[2], s8("hello")));
+        } else if (row == 2) {
+            assert(it.len == 3);
+            assert(s8_are_equal(it.data[0], s8("Alice")));
+            assert(s8_are_equal(it.data[1], s8("27")));
+            assert(s8_are_equal(it.data[2], s8("hi, there")));
+        } else if (row == 3) {
+            assert(it.len == 3);
+            assert(s8_are_equal(it.data[0], s8("Q\"uote\"")));
+            assert(s8_are_equal(it.data[1], s8("")));
+            assert(s8_are_equal(it.data[2], s8("tail")));
+        }
+        row += 1;
+    }
+    assert(row == 4);
+
+    s8_t crlf = s8("a,b\r\nc,d\r\n");
+    row = 0;
+    for (csv_parser_t it = csv_iter(arena, crlf, params); csv_is_valid(&it); csv_advance(&it)) {
+        assert(it.len == 2);
+        if (row == 0) assert(s8_are_equal(it.data[1], s8("b")));
+        if (row == 1) assert(s8_are_equal(it.data[1], s8("d")));
+        row += 1;
+    }
+    assert(row == 2);
+
+    s8_t semi = s8("a;b;\n1;2;\n");
+    params.delimiter = s8(";");
+    row = 0;
+    for (csv_parser_t it = csv_iter(arena, semi, params); csv_is_valid(&it); csv_advance(&it)) {
+        assert(it.len == 3);
+        assert(s8_are_equal(it.data[2], s8("")));
+        row += 1;
+    }
+    assert(row == 2);
+
+    ma_destroy(arena);
+}
+
 fn void test_s8(void) {
     ma_arena_t *arena = ma_create(ma_default_reserve_size);
 
@@ -231,6 +287,7 @@ int main() {
     os_core_init();
     test_s8();
     test_json();
+    test_csv();
     os_test();
     return 0;
 }