Clinical practice guidelines (CPGs) provide recommendations to clinicians based on current medical knowledge to guide and reduce variability in clinical care. With advances in nutrition science research, CPGs increasingly include dietary guidance; however, the degree of consistency in dietary recommendations across CPGs has not been investigated. Using a systematic review approach adapted for meta-epidemiologic research, this study compared dietary guidance from current guidelines developed by governments, major medical professional societies, and large health stakeholder associations owing to their often well-defined and standardized processes for guideline development. CPGs making recommendations for dietary patterns and food groups or components for generally healthy adults or those with prespecified chronic diseases were eligible. Literature from January 2010 to January 2022 was searched in 5 bibliographic databases and augmented by searches in point-of-care resource databases and relevant websites. Reporting followed an adapted PRISMA statement and included narrative synthesis and summary tables. Seventy-eight CPGs for major chronic conditions (autoimmune, 7; cancers, 5; cardiovascular-related, 35; digestive, 11; diabetes, 12; weight-related, 4; or multiple, 3) and general health promotion (n = 1) were included. Nearly, all (91%) made dietary pattern recommendations, and approximately half (49%) endorsed patterns centered on plant foods. Overall, CPGs were most closely aligned in promoting consumption of major plant food groups (vegetables = 74% of CPGs, fruit = 69%, whole grains = 58%), whereas discouraging intake of alcohol (62%) and salt or sodium (56%). CVD and diabetes CPGs were similarly aligned with additional messaging to consume legumes/pulses (60% of CVD CPGs; 75%, diabetes), nuts and seeds (67%, CVD), and low-fat dairy (60%, CVD). Diabetes guidelines discouraged sweets/added sugars (67%) and sweetened beverages (58%). This alignment across CPGs should boost clinician confidence in relaying such dietary guidance to patients in accordance with their relevant CPGs. This trial was registered at the International Prospective Register of Systematic Reviews (https://www.crd.york.ac.uk/prospero; PROSPERO 2021) as CRD42021226281.