Exhibit 32.3

CERTIFICATION OF THE PRINCIPAL FINANCIAL OFFICER

PURSUANT TO18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with this Quarterly Report of GX Acquisition Corp. II (the “Company”) on Form 10-Q for the quarterly period ended September 30, 2022, as filed with the Securities and Exchange Commission (the “Report”), I, Andrea J. Kellett, Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that, to the best of my knowledge:

1. The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company as of and for the period covered by the Report.

Dated: November 8, 2022

/s/ Andrea J. Kellett

Andrea J. Kellett

Chief Financial Officer

(Principal Financial and Accounting Officer)