X0306 4 2022-11-02 0000749251 GARTNER INC IT 0001198849 HALL EUGENE A 56 TOP GALLANT ROAD P.O. BOX 10212 STAMFORD CT 06904-2212 1 1 CEO Common Stock 2022-11-02 4 S 0 895 321.30 D 1159034 D Common Stock 2022-11-02 4 S 0 2467 322.30 D 1156567 D Common Stock 2022-11-02 4 S 0 1000 323.50 D 1155567 D Common Stock 2022-11-02 4 S 0 3984 324.67 D 1151583 D Common Stock 2022-11-02 4 S 0 4106 325.79 D 1147477 D Common Stock 2022-11-02 4 S 0 3600 326.92 D 1143877 D Common Stock 2022-11-02 4 S 0 600 327.70 D 1143277 D This transaction was executed in multiple trades at prices ranging from $320.76 to $321.67. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $321.81 to $322.80. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $323.04 to $324.01. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $324.22 to $325.18. The price above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $325.31 to $326.28. The price above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $326.38 to $327.21. The price above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $327.42 to $328.16. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. /s/ Kevin Tang for Eugene A. Hall 2022-11-04